1. 4.3 Graphing Equations of Lines From Intercepts
Algebra
4.3
Graphing Equations of Lines
From Intercepts

2. Ax + By = C Standard Form The slope is - A B
x coefficient y coefficient constant
The slope is - A B

3. You can graph lines by finding the 2 points where the line crosses the axis lines.
These are called the x-intercept and the y-intercept.

4. The Intercepts y
y intercept (x = 0)
x intercept (y = 0) x

5. Find the y intercept and the x intercept for 2x + 3y = 6
At the y intercept,
x = 0 2 3
2x + 3(0) = 6
2x = 6
x = 3
At the x intercept,
y = 0

6. 2x + 3y = 6 y intercept (0,2) x intercept (3,0) 2(0) + 3y = 6 3y = 6

7. Graphing from Intercepts
STEPS
Leave the equation in its original form.
Set up an x/y table with 0’s filled in x y
y intercept
x intercept
Compute the y intercept and x intercept
values to find the coordinates
4. Plot the 2 points and connect for the line

8. Now you try one……..

9. Find the y intercept and the x intercept for 2x - 6y = -18
At the y intercept,
x = 0 3 -9
2x - 6(0) = -18
2x = -18
x = -9
At the x intercept,
y = 0

10. . . 2x - 6y = -18 y intercept (0,3) x intercept (-9,0) 2(0) - 6y = -18

11. Homework
P , 60-63