Graphing Linear Equations
An equation of the form Ax + By = C is called a linear equation because
its graph is a straight line.
Procedure —
To Graph a Linear Equation Using a Table of Ordered Pairs
Step 1 Make a table of ordered pairs that satisfy the equation.
Step 2 Plot the ordered pairs.
Step 3 Draw a line through the plotted points.
Example 1
Graph 3x + 2y = 6.
Solution
Step 1 Make a table of ordered pairs that satisfy the equation.
| Choose any values for x or y. We
let x equal -1, 0, 2, and 3.
Then, substitute each value for x in the
equation 3x + 2y = 6 and solve for y.
The table of ordered pairs is shown. |
|
x |
y |
|
-1 |
4.5 |
|
0 |
3 |
|
2 |
0 |
|
3 |
-1.5 |
|
Step 2 Plot the ordered pairs.
The points are plotted.
Step 3 Draw a line through the plotted points.
Each point on the line represents a
solution of the equation 3x + 2y = 6.
Note:
We need only two points to plot a line.
However, we plot more than two points as
a check against possible errors.
|