Pre-Algebra 1-8 Graphing on the Coordinate Plane 1-8 Graphing on the Coordinate Plane Pre-Algebra Warm Up Warm Up Problem of the Day Problem of the Day.

Pre-Algebra

1-8 Graphing on the Coordinate Plane1-8 Graphing on the Coordinate Plane

Pre-Algebra

Warm UpWarm Up

Problem of the DayProblem of the Day

Lesson PresentationLesson Presentation

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Warm UpFind the values for y by substituting 1, 3, 5, and 7 for x.

1, 3, 7, 115, 13, 21, 290, 10, 20, 30

Pre-Algebra

1-8 Graphing on the Coordinate Plane

3. y = 5x 52. y = 4x + 11. y = 2x 3

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Problem of the Day

Tomorrow will be four days after the day before Saturday. What is today?

Monday

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Learn to graph points and lines on the coordinate plane.

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Vocabularycoordinate planex-axisy-axisx-coordinatey-coordinateorigingraph of an equation

Pre-Algebra

1-8 Graphing on the Coordinate Plane

The coordinate plane is like a map formed by two number lines, the x-axis and the y-axis, that intersect at right angles. Ordered pairs are the locations, or points, on the map. The x-coordinate and y-coordinate of an ordered pair tell the direction and number of units to move.

(x, y)x-coordinate move right or left

y-coordinate move up or down

Pre-Algebra

1-8 Graphing on the Coordinate Plane

To plot an ordered pair, begin at the origin, the point (0, 0), which is the intersection of the x-axis and the y-axis.

The first coordinate tells how many units to move left or right; the second coordinate tells how many units to move up or down.

Pre-Algebra

1-8 Graphing on the Coordinate Plane

(2, 3)

The sign of a number indicates which direction to move. Positive: up or right Negative: down or left

Helpful Hint

x

y

origin

(2, 3)move right 2 units

move up 3 units

(0, 0)

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Additional Example 1: Finding the Coordinates of Points on a Plane

Give the coordinates of each point.

Point R is _______.(1, 3)

1 unit right, 3 units up

Point S is _______.(0, –4)

0 units right, 4 units down

Point T is _______.(–2, 2)

2 units left, 2 units up

Point U is _______.(–3, 0)

3 units left, 0 units up

x

y

R

S

T

U

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Try This: Example 1

Give the coordinates of each point.

Point J is _______.(0, 2)

0 units right, 2 units up

Point M is _______.(2, 0)

2 units right, 0 units up

Point K is _______.(–1, 4)

1 unit left, 4 units up

Point P is _______.(–3, –2)

3 units left, 2 units down

x

y

J

P

K

M

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Additional Example 2: Graphing Points on a Coordinate Plane

Graph each point on the coordinate plane. Label the points A-D.

A. (3, 4)right 3, up 4

B. (4, 0)right 4, up 0

C. (–4, 4)left 4, up 4

D. (–1, –3)left 1, down 3

x

y

A

B

D

C

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Try This: Example 2

Graph each point on the coordinate plane. Label the points A-D.

A. (2, 4)right 2, up 4

B. (2, 0)right 2, up 0

C. (–2, 4)left 2, up 4

D. (–1, –1)left 1, down 1

x

y

A

BD

C

Pre-Algebra

1-8 Graphing on the Coordinate Plane

The graph of an equation is the set of all ordered pairs that are solutions of the equation.

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Additional Example 3A: Graphing an Equation

Complete the table of ordered pairs. Graph the equation on a coordinate plane.

x

yA. y = 3x

x 3x y (x, y) 0

1

2

3

3(0) 0 (0, 0)

3(1) 3 (1, 3)

3(2) 6 (2, 6)

3(3) 9 (3, 9)

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Additional Example 3B: Graphing an Equation

Complete the table of ordered pairs. Graph the equation on a coordinate plane.

x

y

B. y = 2x – 3

x 2x – 3 y (x, y) 0

1

2

3

2(0) – 3 –3 (0, –3)

2(1) – 3 –1 (1, –1)

2(2) – 3 1 (2, 1)

2(3) – 3 3 (3, 3)

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Try This: Example 3A

Complete the table of ordered pairs. Graph the equation on a coordinate plane.

x

yA. y = 2x

x 2x y (x, y) 0

1

2

3

2(0) 0 (0, 0)

2(1) 2 (1, 2)

2(2) 4 (2, 4)

2(3) 6 (3, 6)

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Try This: Example 3B

Complete each table of ordered pairs. Graph each equation on a coordinate plane.

x

y

B. y = 3x – 4

x 3x – 4 y (x, y) 0

1

2

3

3(0) – 4 –4 (0, –4)

3(1) – 4 –1 (1, –1)

3(2) – 4 2 (2, 2)

3(3) – 4 5 (3, 5)

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Lesson Quiz: Part 1

Give the coordinates of each point.

1. A

2. B

Graph each point on the given coordinate plane. Label points C, D.

3. C (5, –2)

4. D (0, 4)

(3, 4)

(2, 0)

x

y

A

B D

C

Pre-Algebra

1-8 Graphing on the Coordinate Plane

Lesson Quiz: Part 2

Complete the table. Graph the equation on the given coordinate plane.

5. y = 4x – 3

x

y

(0, 3)

(1, 1)

(2, 5)

x 4x – 3 y (x, y)

0

1

2

4(0) 3

4(1) 3

4(2) 3

3

1

5

(0, 3)

(1, 1)

(2, 5)