Day 3

Graphing Linear Equations Using Intercepts

EMAT6690

by Chris Reid

Graph a line using the x-intercept and the y-intercept.

Example 1:

Graph the line that has the given intercepts.

x-intercept: 4

y-intercept: -2

Solution:

Plot the point (4, 0). Plot the point (0, -2). Draw a line through the points. Example 2:

Find the x-intercept and the y-intercept of the equation. Graph the equation using the intercepts.

6x - 3y = -12

Solution:

To find the x-intercept of the graph of the equation, let y=0.

6x - 3y = -12

6x - 3(0) = -12

6x = -12

x = -2 The x-intercept is -2. The point is (-2, 0).

To find the y-intercept of the graph of the equation, let x=0.

6x - 3y = -12

6(0) - 3y = -12

-3y = -12

y = 4 The y-intercept is 4. The point is (0, 4).

Plot these points and draw a line through them. Assignment:

Find the x-intercept and the y-intercept of each equation. Graph each equation using the intercepts.

1. 4x - 5y = 20

2. -2x + 9y = -18

3. 6x + y = 12

4. x + 7y = -21

5. -2x + 4y = 16

6. y = 2x - 4

7. y = x + 3

8. y = -x + 2

9. y = 3x - 6

10. y = -2x + 3