1.5 quadratic equations. warm-up factor: x 2 + 20x +100x 2 + 12x +36 x 2 – 24x + 144x 2 – 16x +...

1.5 Quadratic Equations

WARM-UP• Factor:

x2 + 20x +100 x2 + 12x +36

x2 – 24x + 144 x2 – 16x + 64

• Solve: 2x2 + 6x - 3 = 5x + 3

• Which homework questions do you need help with???

Write the numbers here

Factor these:

• x2 + 10x + 25

• x2 - 14x + 49

• x2 – 20x + 100

=(x+5)(x+5) = (x+5)2

=(x-7)(x-7) = (x-7)2

=(x-10)(x-10) = (x-10)2

PERFECT SQUARE TRINOMIALS!!!

Complete the Square (visual)

x2

x

x

x

x

1 x

1 x

1 x

1 x

x2 +8x

x2 +8x+______16

(x+4)2

TRY TO COMPLETE THE SQUARE:

• x2 + 6x + ________ =

• x2 + 18x + ________ =

• x2 – 12x + ________ =

Completing the Squareas described in the textbook….

If x2 + bx is a binomial, then by adding (b/2) 2, which is the square of half the coefficient of x, a perfect square trinomial will result.

That is, x2 + bx + (b/2)2 = (x + b/2)2

Applying the idea to SOLVING QUADRATIC

EQUATIONSx2 = 16

x2 = 25

(x+5)2 = 36

If you can get your equation to a point like this,

you can easily for x!!!

Activity

See if you can put the problem in order.

CHECK ANOTHER GROUP’S WORK USING STICKY NOTES

If you agree, write “OK” on your sticky note.

If you disagree, give them a sticky note indicating the changes you’d make.

Activity

PracticeWorksheet #2 & 4

Harder problems

Worksheet #9-10

HOMEWORK PROBLEMS #1-15, skip #10

DAY #2 – What if it doesn’t divide evenly.