Ordered pairs are used to locate points in a coordinate plane.

x-axis (horizontal axis)

origin (0,0)

y-axis (vertical axis)5

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-5

-5

In an ordered pair, the first number is the x-coordinate. The second number

is the y-coordinate. Graph. (-3, 2)

•

5

5

-5

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The x-axis and y-axis separate the coordinate plane into four regions, called quadrants.

II

(-, +)

I

(+, +)

IV

(+, -)

III

(-, -)

Origin (0,0)

(3,-2)

(-4,0)

Quandrant IV (+, - )

Quandrant III (-, - )

Quandrant II (-, + )

Quandrant I (+, + )

Origin (0,0)

(3,-2)

(-4,0)

Quandrant IV (+, - )

Quandrant III (-, - )

Quandrant II (-, + )

Quandrant I (+, + )

1. I2. II3. III4. IV5. None – x-axis6. None – y-axis

1. I2. II3. III4. IV5. None – x-axis6. None – y-axis

1. I2. II3. III4. IV5. None – x-axis6. None – y-axis

Example 1: Give the coordinates of the point.

JI

HG

F

ED

C

BA(-4,3) (0,3)

(1,4)

(1,0)

(5,1)

(3,-4)

(0,-3)

(-4,-4)

(-3,0) (0,0)

Example 2: Plot the point in a coordinate plane. Describe the location of the point.

a) A(-4,9) b) B(5,0) c) C(0,-8) d) D(7, -2)

A(-4,9)

B(5,0)

C(0,-8)

D(7,-2)

x y = ½x + 1 y

-4 y = ½(-4) + 1

-2 y = ½(-2) + 1

0 y = ½(0) + 1

2 y = ½(2) + 1

4 y = ½(4) + 1

Example 3: Graph the function y = ½x + 1 with the following values of x: -4, -2, 0, 2, and 4.

Step 1: Make a table

x y = ½x + 1 y

-4 y = ½(-4) + 1

-2 y = ½(-2) + 1

0 y = ½(0) + 1

2 y = ½(2) + 1

4 y = ½(4) + 1

x y = ½x + 1 y

-4 y = ½(-4) + 1 -1

-2 y = ½(-2) + 1 0

0 y = ½(0) + 1 1

2 y = ½(2) + 1 2

4 y = ½(4) + 1 3

What is the ordered pair for A?

1. (3, 1)2. (1, 3)3. (-3, 1)4. (3, -1)

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• A

What is the ordered pair for C?

1. (0, -4)2. (-4, 0)3. (0, 4)4. (4, 0)

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5

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• C