factoring, exponents, and functions notes.notebook...jan 29, 2015 · factoring, exponents, and...
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Factoring, Exponents, and Functions Notes.notebook
1
January 29, 2015
This material is made freely available at www.njctl.org and is intended for the noncommercial use of students and teachers. These materials may not be used for any commercial purpose without the written permission of the owners. NJCTL maintains its website for the convenience of teachers who wish to make their work available to other teachers, participate in a virtual professional learning community, and/or provide access to course materials to parents, students and others.
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New Jersey Center for Teaching and Learning
Progressive Mathematics Initiative Algebra II
Fundamental Skills of
Algebra
www.njctl.org
20130724
Table of Contents
Factoring
Exponents
Functions
click on the topic to go to that section
Factoring
Return to Table of Contents
Factoring
Goals and ObjectivesStudents will be able to factor complex expressions and solve equations using factoring.
Factoring
Why do we need this?The more we can simplify a problem, the easier it is to solve. Factoring allows us to break up expressions into smaller parts and, much of the time, simplify our
strategies to solve them.
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Factoring
Multiply the following:
3x(2x2 + 5) (x + 3)(x 9) (2x 1)(3x 4)
Answer
Factoring
Factoring is undoing what you just did. It breaks up expressions into parts and pieces.
Factoring
Factor out the GCF (greatest common factor).
8x + 32y 5a2b 10ab 12a3b2 + 4ab2
Answer
8x + 32y8(x + 4y)
*If students struggle with this have them write out each term as lowest common factors. For example:
8x+32y=2*2*2*x+2*2*2*2*2y OR 5a2b10ab=5*a*a*b2*5*a*b
Students can then match the pieces each term has in common.
Factoring
You can easily check your answer by distributing the GCF back to all of your terms.
Factor then check your answer:
3x2y2 + 12xy2 + 6y2 6m4n3 + 18m3n2 36m2n
Answer
3x2y2 + 12xy2 + 6y23y2(x2 + 4x + 2)
1 What is the GCF of the following expression? 24a3b3c 6ab3c
A 6a3b3c B 6abc C ab3c D 6ab3c E a3b3c
Factoring
Answer
2 Factor:
A 3m5n2(4 n 5m)
B m5n2(12 3n 15m)
C 3m6n3(4 5n)
D 3m4n2(4mn 5m2)
E 3m4n2(4 mn 5m2)
Factoring
12m4n2 3m5n3 15m6n2
Answer
Factoring, Exponents, and Functions Notes.notebook
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3 Factor out the GCF:
A x2y2z3(x2 xy + y2)
B xyz(x2 xy + y2)
C x3y2z3(x y y2)
D x2y3z3(x2 x y)
E x2y2z3(x xy + y2)
x4y2z3 x3y3z3 + x2y4z3Factoring
Answer
4 Factor the following:
A 4x3y2(2x + 3y)
B 4x3y2(2x 3y)
C 8x3y2(x + 4y)
D 8x3y2(x 4y)
E 8x4y2(1 4y)
8x4y2 12x3y3Factoring
Answer
5 Factor out the GCF: 15m3n 25m2 15mn3
A 15m(mn 10m n3)
B 5m(3m2n 5m 3n3)
C 5mn(3m2 5m 3n2)
D 5mn(3m2 5m 3n)
E 15mn(mn 10m n3)
Factoring
Answer
6 Factor:
A m3n3(2m 2)
B 2mn(m3n + m)
C 2mn(m3n m)
D 2m3n3(m2 + 1)
E 2m3n3(m2 1)
Factoring
2m4n3 2m3n3
Answer
7 Factor out the GCF:
A 14p3q7(1p 14)
B 14p2q6(pq 14)
C 14p2q6(pq 2)
D p3q6(14q 28)
E 14pq(p2q6 2pq5)
Factoring
14p3q7 28p2q6
Answer
Factoring
Factoring quadratics of the form x2 + bx + c.
Try: x2 x 6
Answer
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Factoring
Here are some tips to help you factor:
Read the expression backwards:
x2 x 6
"factors of 6 that subtract to 1"
x2 + 6x + 8
"factors of 8 that add up to 6"
Factoring
The signs in front of c will also help you factor:
x2 + bx + c ⇒ (x + m)(x + n)
x2 bx + c ⇒ (x m)(x n)
x2 + bx c
x2 bx c
If the sign in front of c is +: If the sign in front of c is :
(x m)(x + n)⇒
⇒
same signs, both +
same signs, both
different signs
different signs
Factoring
Here is the last tip...
Use a factor tree to help you find the factors of c. If none of the pairs add or subtract to the middle term, the quadratic is not factorable.
Factor trees: 12
>
1 122 63 4
24
>
1 242 123 84 6
48
>
1 482 243 164 126 8
72
>
1 722 363 244 186 128 9
Factoring
x2 + 6x + 8
Read it backwards: "factors of 8 that add up to 6."
Use the pattern from c: "same signs, both +."
Now factor it!
Answer
Factoring
Use the tips to help you factor the following quadratics.
x2 5x 24 a2 13a + 30 m2 + 4m 35
Answer
x2 5x 24(x 8)(x + 3)
Factoring
Try...x2 8xy + 16y2
Answer
Factoring, Exponents, and Functions Notes.notebook
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8 Factor the trinomial:
A (x 7y)(x + 6y)
B (x + 7y)(x 6y)
C (x 42y)(x + y)
D (x + 42y)(x y)
E Solution not shown
Factoring
x2 xy 42y2
Answer
9 Factor:
A (x 12)(x + 2)
B (x + 12)(x 2)
C (x 6)(x +4)
D (x 6)(x 4)
E Solution not shown
Factoring
x2 10x + 24
Answer
10 Factor the quadratic:
A (x + 5)(x + 1)
B (x 4)(x 1)
C (x + 2)(x + 3)
D (x + 1)(x 4)
E Solution not shown
x2 + 5x + 4Factoring
Answer E
Answer is (x + 4)(x + 1)
11 Factor:
A (x 12)(x 6)
B (x 6)(x 3)
C (x 6)(x + 3)
D (x 9)(x + 2)
E Solution not shown
x2 3x 18
Factoring
Answer
12 Factor:
A (x 5)(x 5)
B (x 5)(x + 5)
C (x + 15)(x + 10)
D (x 15)(x 10)
E Solution not shown
Factoring
x2 + 10x + 25
Answer
FactoringFactoring quadratics of the form ax2 + bx + c.
3x2 + 17x + 10
With just a few extra steps, you can factor quadratics with a leading coefficient (a) just like the previous ones.
Mulitiply a and c ⇒ x2 + 17x + 30Factor the result ⇒ (x + 15)(x + 2)
Divide the numbers by a ⇒ (x + 15)(x + 2) 3 3
Reduce any fractions ⇒ (x + 5)(x + 2)3
Move any remaining denominators ⇒ (x + 5)(3x + 2)
The answer is (x + 5)(3x + 2) Teacher N
otes There are other methods you can
use to factor these. This is one of the most efficient ways. Students catch on quickly. The most common mistake is forgetting to divide and/or reduce.
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Factoring
Try this one. Make sure you reduce the fractions where possible.
10x2 31x + 15
Answer
Factoring
Here is another one to practice on...
3x2 + 5x 2
Answer
Factoring
Try... 4x2 + 4x +1
Answer
13 Factor:
A (6x 5)(x 6) B (6x 1)(x 6) C (3x 2)(2x + 3) D (3x + 2)(2x 3) E Solution not shown
Factoring
6x2 5x 6
Answer
14 Factor the following:
A (2x 1)(5x + 3) B (2x + 1)(5x + 3) C (10x 1)(x + 3) D (10x 1)(x 3) E Solution not shown
10x2 11x + 3
Factoring
Answer
15 Which is a factor of ?
A (4x + 5)B (2x + 3)C (12x + 5)D (3x + 5)E (4x + 2)
12x2 + 23x + 10Factoring
Answer
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16 Which is a factor of the quadratic?
A (x 7y)B (2x 8y)C (2x 6y)D (x 8y)E (2x y)
Factoring
2x2 23xy + 56y2
Answer
17 Which of the following is a factor of ?
A (2x 3y)B (5x 3y)C (3x 2y)D (3x + 5y)E (2x 5y)
6x2 19xy + 15y2Factoring
Answer A
Solution is (2x 3y)(3x 5y)
18 Factor:
A (x 4y)(4x + 2y)B (x 8y)(4x + y)C (2x + 4y)(2x + 2y)D (4x + y)(x + 8y)E Solution not shown
Factoring
Answer
Factoring
Multiply:
(2x + 3)(2x 3) (x + 3)(x2 3x + 9)
Answer
(2x + 3)(2x 3)4x2 9
To factor the difference of squares, the difference of cubes and the sum of cubes, use the following formulas:
Factoring
a2 b2 ⇒ (a b)(a + b)
a3 b3 ⇒ (a b)(a2 + ab + b2)
a3 + b3 ⇒ (a + b)(a2 ab + b2)
Try...
Factoring
4p2 q2 16m2 1 64p3 + y3
a2 b2 ⇒ (a b)(a + b)a3 b3 ⇒ (a b)(a2 + ab + b2)a3 + b3 ⇒ (a + b)(a2 ab + b2)
Answer
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Factoring
a2 b2 ⇒ (a b)(a + b)a3 b3 ⇒ (a b)(a2 + ab + b2)a3 + b3 ⇒ (a + b)(a2 ab + b2)Factor...
25x2 81y2 x3y3 + 1 8m3 125n3
Answer
19 Factor:
A (11m 10n)(11m + 10m) B (121m n)(m + 100n) C (11m n)(11m + 100n) D Not factorable E Solution not shown
121m2 + 100n2Factoring
Answer
20 Factor:
A (3m 8np)(3m + 8np) B (3m + 4np)(3m2 12mnp + 4n2p2) C (3m + 4np)(9m2 12mnp + 16n2p2) D Not factorable E Solution not shown
Factoring
27m3 + 64n3p3
Answer
21 Factor:
A (a 5b)(a + 5b) B (a 5b)(a2 + 5ab + 5b2) C (a + 5b)(a2 5ab + 25b2) D Not FactorableE Solution not shown
Factoring
a3 125b3
Answer
22 Factor:
A (m + n)(m n) B (m + n)(m + n) C (m n)(m n) D Not factorableE Solution not shown
Factoring
m2 n2
Answer
23 Factor:
A (d 1)(d + 1) B (d 1)(d2 + d + 1) C (d + 1)(d2 d + 1) D Not factorableE Solution not shown
Factoring
d3 1
Answer
Factoring, Exponents, and Functions Notes.notebook
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24 Factor:
A (3m + 2n)(3m 2n) B (3m + 2n)(9m2 6mn + 4n2) C (3m 2n)(9m2 + 6mn + 4n2) D Not factorableE Solution not shown
Factoring
27m3 + 4n3
Answer
25 Factor:
A (16x 2y)(16x + 2y) B (6x 2y)(6x2 + 12xy + 2y2) C (6x 2y)(36x2 + 12xy + 4y2) D Not factorableE Solution not shown
Factoring
216x3 8y3
Answer
Factoring
Factoring by Grouping.
What happens when there are 4 terms?
4ap 4a + 3xp 3x
Answer
Factoring
Try... xy + 4x 3y 12
Answer
Factoring
Two more...pq + 4p + 3q + 12 mn pm qn + qp
Answer
pq + 4p + 3q + 12p(q + 4) + 3(q + 4)(p + 3)(q + 4)
26 Factor by grouping:
A (r + 4)(s 7) B (r 7)(s + 4) C (rs 7)(rs + 4) D Not factorableE Solution not shown
Factoring
rs 7r + 4s 28
Answer
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27 Factor:
A (n 3)(m + 4n) B (n 3)(m 4n) C (n + 4)(m n) D Not factorableE Solution not shown
Factoring
mn + 3m 4n2 12n
Answer
28 Factor:
A (3k 2)(g + 6) B (3g + 2)(k 6) C (3k 2)(g + 6) D Not factorableE Solution not shown
Factoring
3gk 18g + 2k 12
Answer
29 Factor by grouping:
A (m 4)(2p 7) B (m + 7)(2p + 4) C (m 4)(2p + 7) D Not factorableE Solution not shown
Factoring
2mp 8p 7m + 28
Answer
30 Factor by grouping
A (x + 4)(2y + 3) B (x + 4)(2y 3) C (x 3)(2y + 4) D Not factorableE Solution not shown
2xy + 3x + 8y 12Factoring
Answer
31 Factor:
A (3m 5)(p + 2n) B (3m + 5)(p 2n) C (3m 2n)(p + 5) D Not factorableE Solution not shown
Factoring
3mp + 15m 2np 10n
Answer
Now, let's combine all of the situations. In any factoring problem, factor out the GCF first.
Factoring
Factor these completely...
2x3 22x2 + 48x 3m3n + 3m2n 18mn
Answer
2x3 22x2 + 48x2x(x2 11x + 24)2x(x 8)(x 3)
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Factoring
Factor completely...
4x3 32y3 54a4 + 2ab3
Answer 4x3 32y3
4(x3 8y3)4(x 2y)(x2 + 2xy + 4y2)
32 Factor completely:
A 3mn(2m 1)(m 3) B 3mn(2m + 1)(m 3) C 3n(2m 1)(m2 + 3m + 9) D Not factorableE Solution not shown
Factoring
6m3n + 21m2n 9mn
Answer
33 Factor completely:
A 3(2p + 5)(4p3 10p + 25) B 3p(16p2 + 25) C 3p(4p 5)(4p 5) D Not factorableE Solution not shown
Factoring
48p3 + 75p
Answer
34 Factor completely:
A (4p2 3)(m 4) B 4p2(pm 4)(pm 3) C 4p2m(m 4)(p + 3) D Not factorableE Solution not shown
Factoring
4p3m 12p3 16mp2 + 48p2
Answer
35 Factor completely:
A 2xy(9x 1) B 2xy(3x 1)(3x + 1) C 2y(9x2 x) D Not factorableE Solution not shown
Factoring
18x3y 2xy
Answer
36 Factor completely:
A 8ab(a2 + 4) B 4ab(2a2 + a + 3)C 4ab(2a + 3)(a 1)D Not factorableE Solution not shown
Factoring
8a3b 4a2b + 12ab
Answer
Factoring, Exponents, and Functions Notes.notebook
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37 Factor completely:
A 2b(4b 1)(3b + 2) B 4b(6b2 + 6b 1) C 2b(4b + 1)(3b 2) D Not factorableE Solution not shown
24b3 + 10b2 4b
Factoring
Answer
Factoring is often use to solve equations that are in polynomial form.
Factoring
Steps: 1) Move all terms to one side of the equation. (the other side becomes zero)
2) Factor the resulting polynomial.3) Set each factor equal to zero.4) Solve each equation. 5) Write the answers clearly.
Factoring
Solve the equation by factoring:
x2 = 9x 18
Answer
One more...
Factoring
6x3 + 10x2 = 4x
Answer
Another example...
Factoring
6m2 = 9m 24m3
Answer
38 Which of the following are solutions to the equation?
A 0B 1C 3/2D 3/2E 4F 4G 4/3H 4/3
Factoring
16x3 36x = 0
Answer
Factoring, Exponents, and Functions Notes.notebook
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39 Find all of the solutions to:
A 0B 1C 1D 3E 3F 4G 4H 12
Factoring
3m3 + 3m2 = 36m
Answer
40 Solve for p:
A 0B 1/2C 1/2D 2/5E 2/5F 4/3G 5/2H 5/2
Factoring
29p2 + 10p = 10p3
Answer
41 Find the values for n:
A 0B 1/2C 1/2D 1/3E 2/3F 2/3G 4H 4
Factoring
18n4 + 48n2 = 84n3
Answer
42 Find x:
A 0B 1/4C 1/4D 1/3E 1/3F 1/2G 1/2H 3
Factoring
6x4 = 5x3 x2
Answer
43 Solve by factoring:
A 0B 1/4C 1/4D 1/2E 1/2F 1G 2H 2
Factoring
p2 + p = 2p3
Answer
Exponents
Return to Table of Contents
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Exponents
Goals and ObjectivesStudents will be able to simplify complex expressions containing exponents.
Exponents
Why do we need this?Exponents allow us to condense bigger
expressions into smaller ones. Combining all properties of powers
together, we can easily take a complicated expression and make it
simpler.
Exponents
Rules for working with exponents:
Exponents
Multiplying powers of the same base:
(x4y3)(x3y)
Teacher N
otes Have students think about what the expression
means and then use the rule as a short cut.
For example: (x4y3)(x3y) = x x x x y y y x x x y = x7y4
The rules are a quick way to get an answer.
Exponents
(3a3b2)(2a4b3)
Simplify:
(4p2q4n)(3p3q3n)
Answer
Work out:
Exponents
xy3 x5y4. (3x2y3)(2x3y)
Answer
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44 Simplify:
A m4n3p2 B m5n4p3 C mnp9 D Solution not shown
(m4np)(mn3p2)Exponents
Answer
45 Simplify:
A x4y5 B 7x3y5 C 12x3y4 D Solution not shown
Exponents
(3x3y)(4xy4)
Answer
D
(3x3y)(4xy4)12x4y5
46 Work out:
A 6p2q4 B 6p4q7 C 8p4q12 D Solution not shown
Exponents
2p2q3 4p2q4.
Answer
D
2p2q3 4p2q48p4q7
47 Simplify:
A 50m6q8 B 15m6q8 C 50m8q15 D Solution not shown
Exponents
.5m2q3 10m4q5
Answer
48 Simplify:
A a4b11 B 36a5b11 C 36a4b30 D Solution not shown
(6a4b5)(6ab6)
Exponents
Answer
Exponents
Dividing powers with the same base:
Teacher N
otes
Have students think about what the expression means and then use the rule as a short cut.
For example:
The rules are a quick way to get an answer.
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Exponents
Simplify:
Answer
Exponents
Try...
Answer
49 Divide:
A
B
C
D Solutions not shown
Exponents
Answer
50 Simplify:
A
B
C
D Solution not shown
Exponents
Answer
D
51 Work out:
A
B
C
D Solution not shown
Exponents
Answer
52 Divide:
A
B
C
D Solution not shown
Exponents
Answer
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53 Simplify:
A
B
C
D Solution not shown
Exponents
Answer
D
Exponents
Power to a power:
Teacher N
otes
Have students think about what the expression means and then use the rule as a short cut.
For example:
The rules are a quick way to get an answer.
Exponents
Simplify:
Answer
Try:
Exponents
Answer
54 Work out:
A
B
C
D Solution not shown
Exponents
Answer
55 Work out:
A
B
C
D Solution not shown
Exponents
Answer
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56 Simplify:
A
B
C
D Solution not shown
Exponents
Answer
57 Simplify:
A
B
C
D Solution not shown
Exponents
Answer
D
58 Simplify:
A
B
C
D Solution not shown
Exponents
Answer
Negative and zero exponents:Exponents
Why is this? Work out the following:
Teacher N
otes
Exponents
Sometimes it is more appropriate to leave answers with positive exponents, and other times, it is better to leave answers without fractions. You need to be able to translate expressions into
either form.
Write with positive exponents: Write without a fraction:
Answer
Exponents
Simplify and write the answer in both forms.
Answer
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Exponents
Simplify and write the answer in both forms.
Answer
Exponents
Simplify:
Answer
Exponents
Write the answer with positive exponents.
Answer
59 Simplify and leave the answer with positive exponents:
A
B
C
D Solution not shown
Exponents
Answer
60 Simplify. The answer may be in either form.
A
B
C
D Solution not shown
Exponents
Answer
61 Write with positive exponents:
A
B
C
D Solution not shown
Exponents
Answer
D
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62 Simplify and write with positive exponents:
A
B
C
D Solution not shown
Exponents
Answer
D
63 Simplify. Write the answer with positive exponents.
A
B
C
D Solution not shown
Exponents
Answer
64 Simplify. Write the answer without a fraction.
A
B
C
D Solution not shown
Exponents
Answer
CombinationsExponents
Usually, there are multiple rules needed to simplify problems with exponents. Try this one. Leave your answers with positive exponents.
Answer
Exponents
When fractions are to a negative power, a short cut is to flip the fraction and make the exponent positive.
Try...
Answer
Exponents
Two more examples. Leave your answers with positive exponents.
Answer
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65 Simplify and write with positive exponents:
A
B
C
D Solution not shown
Exponents
Answer
D
66 Simplify. Answer can be in either form.
A
B
C
D Solution not shown
Exponents
Answer
67 Simplify and write with positive exponents:
A
B
C
D Solution not shown
Exponents
Answer
68 Simplify and write without a fraction:
A
B
C
D Solution not shown
Exponents
Answer
Operations with Functions
Return toTable ofContents
Goals and ObjectivesStudents will be able to manipulate multiple functions algebraically and simplify resulting
functions.
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Why do we need this?In this unit, we will graphically explored transformations of functions. Sometimes, data is more complex and requires more than one representative function. Algebraically, manipulating functions allows us to combine different functions together and results in
many more options for real life situations.
Here are the properties of combining functions:
Adding functions:
Subtracting functions:
Multiplying functions:
Dividing functions:
Operations with Functions
Answer
Given: and
Find: Simplify your
answers as much as possible.
What happens to the domain?
Operations with Fractions
Answer
Given: and
Find:
Operations with Functions
Answer
69 Given and , find
A
B
C
D Answer
70 Given
A
B
C
D
and , find h(x) if
Answer
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71 Given and , find
A
B
C
D
Answer
72 Given and , find
A
B
C
D Answer
Function Notation
For example: y = 3x + 2 becomes f(x) = 3x + 2
*f(x) = 3x + 2 is still a line with a slope of 3 and a yintercept of 2.
Mathematically, nothing changes. Yet, when a relation is a function, instead of writing y mathematicians use f(x), read "f of x."
So why change the notation?
1) It lets the mathematician know the relation is a function.
2) If a second function is used, such as g(x) = 4x, the reader will be able to distinguish between the different functions.
3) The notation makes evaluating at a value of x easier to read.
Function Notation
Evaluating a Function To Evaluate in y = Form:
Find the value of y = 2x + 1when x = 3
y = 2x + 1y = 2(3) + 1
y = 7
When x is 3, y = 7
To Evaluate in Function Notation:
Given f(x) = 2x + 1 find f(3)
f(3) = 2(3) + 1f(3) = 7
"f of 3 is 7"
Similar methods are used to solve but function notation makes asking and answering questions more concise.
Evaluate the function at each given value:
Answer
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January 29, 2015
Evaluate the functions at each given value:
Answer
Find:
Evaluate the functions You can also substitute expressions in for values of x.
Answer
73 Given and Find the value of .
Answer
74 Given and Find the value of .
Answer
75 Given and Find the value of .
Answer
76 Given and Find the value of .
Answer
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77 Given and Find:
A
B
C
D
E
Answer
78 Given and Find:
A
B
C
D
E
Answer
79 Given and Find:
A
B
C
D
E Answer
Given and , find:
a)
b)
c)
d)
You may also be asked to evaluate combined functions when given specific values for x.
Combined Functions
Answer
80 Given and , find
A
B
C
D
6
4
12
10
Answer
81 Given and , find
A
B
C
D
1728
864
864
1288
Answer
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82 Given and , find
A
B
C
D
undefined
Answer
Expressions may also be used to create more complex functions.
If and , create .
Leave your answer in terms of x.
Answer
If and , create .Leave your answer in terms of x.
Answer
If and , create .
Leave your answer in terms of x.
Answer
83 If and , create .
Is this equivalent to ?
Yes
No Answer
84 If and , create .
Is this equivalent to ?
Yes
No
Answer
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85 If and , create .
Is this equivalent to ?
Yes
No
Answer
Composite Functions
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or
Goals and ObjectivesStudents will be able to recognize function notation and correctly unite two or more functions together to
create a new function.
Why do we need this?On many occasions, multiple situations happen to something before it obtains a final result. For example, you take extra food off of your plates before you put them in the dishwasher. Or, to wrap a present you must first put it in the box, then apply the wrapping paper, and finally tie the bow. These are multiple
functions that go together to obtain a desired result.
Composite functions exist when one function is "nested" in the other function.
There are 2 ways of writing a composite function:
Each form is read "f of g of x" and both mean the same thing.
or
Composite FunctionsTo simplify composite functions, substitute one function into the other in place of "x" and simplify. Work from the inside out.
Given:
Find: Find:
Composite Functions
Answer f(g(x)) = f(g(x))
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Given:
Find: Find:
Composite Functions
Answer
To simplify composite functions with numerical values, substitute the number into the "inner" function, simplify, and then substitute that value in for the variable in the "outer" function.
Given:
Find:
Composite Functions
Find:
Answer
86 If and , find the value of
A B C D
Answer
87 Find if
A B C D
Answer
88 Find
A B C D A
nswer
89 Find
A
B
C
D
Answer
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90 Find if
A
B
C
D
Answer
91 Find if and
A
B
C
D
62
88
82
19
Answer
Inverse Functions
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Goals and ObjectivesStudents will be able to recognize and find an inverse function:
a) using coordinates,b) graphically and c) algebraically.
Why do we need this?Sometimes, it is important to look at a problem from
the inside out. Addition undoes subtraction. Multiplication undoes division. In order to look deeply into different problems, we must try to see things from the inside out. Inverse functions undo original functions.
Def: An inverse function is a function that undoes another function. The notation for the inverse of is .
You can prove that a function is an inverse of another using the following relationship:
Read, "the inverse of f of x."
Example: Prove that f(x) and g(x) are inverse functions.
Inverse Function
Answer
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You can also prove that two functions are inverses by GRAPHING. The graph of an inverse is the reflection of the function over y = x.
The following functions are inverses of each other. Look at their graphs and make a conjecture about the x and y values of inverse functions.
Inverse Function
Teacher N
otes The inverse of a function is the reflection over y = x. As you
observed, this will result in the switching of x and y values.
Examples:
a) Find the inverse of: b) Find the inverse of:
f(x)= {(1, 2), (3, 5), (7, 6)} X Y
3 2
4 4
5 5
6 7
Inverse Function
Answer
92 What is the inverse of {(1, 4), (5, 3), (2, 1)}?
A {(4,1), (3,5), (2,1)}
B {(1,4), (5,3), (2,1)}
C {(4,1), (3,5),(1,2)}
D {(4,1), (3,5), (1,2 )} Answer
93 If the inverse of a function is {(1, 0), (3, 3), (4, 5)}, what was the original function?
A {(0,1), (3,3), (5,4)}
B {(1,4), (5,3), (2,1)}
C {(0,1), (3,3),(4,5)}
D {(0,1), (3,3), (4,5)} Answer
94 What is the inverse of:A B
C D
Answer
95 Will the inverse of the following points be a function? Why or why not?
Yes
No
Answer
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Draw the inverse of the given function.
Is the inverse a function? Why or why not?
Answer
InverseDraw the inverse of the given function.
Is the inverse a function? Why or why not?
Inverse
Answer
Just like the Vertical Line Test, there is a simple way to determine if a function's inverse is also a function, just from looking at its graph.Def: The Horizontal Line Test is used to determine if a function has an inverse. If a horizontal line crosses the function more than once, it WILL NOT have an inverse.
Move this line to check:
Answer
Technically, the horizontal line test is checking to see if the inverse is a function. Every function has an inverse, but it isn't necessarily a function.
This one does not pass!
Horizontal Line TestExample: Will the inverse of the given function be a function?
10 8 6 4 2 0 2 4 6 8 10
1098765432
12345678910
x
y
Move this line to check:
Answer
Horizontal Line Test
96 Which graph is the inverse of the function at right?
A B C D
A B C D
Answer
97 Which graph is the inverse of the function at right?
A B
C D Answer
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98 Which graph is the inverse of the function at right?
C D B A Answer
99 Will the inverse of be a function?
Yes
No
Answer
Knowing that the inverse of a function switches x and y values, we can take this concept further when given an equation.
Given: Switch x and y. Solve for y: Inverse function:
Finding the Inverse of a Function Algebraically
InversePractice: Find the inverse of the following functions.
Answer
Answer
InversePractice: Find the inverse of the following function.
100 Which of the following choices is the inverse of
A
B
C
D
Answer
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101 Which of the following is the inverse of
A
B
C
D
Answer
102 Find the inverse of
A
B
C
D
Answer
103 Find the value of
A
B
C
D
0
1
2
1
Answer