algebra I

Graphing equations in slope-intercept form quickly


The slope-intercept form of a linear equation, y = mx + b, is convenient for quickly graphing the equation.

We will graph the equation y = 1/2x − 4. The slope is m = 1/2 and the y-intercept is b = −4.


If m is not a fraction, you can write it as a fraction to identify the rise and the run. For instance, if the slope is −3, state it as −3/1. The rise is −3, the run is 1. The following activity walks you through the steps to graph the equation y = −3x + 1.

This activity helps you practice graphing a line using the y-intercept.


Graph the y-intercept. Then use the slope to find another point on the line and graph it. When you have graphed two correct points, the computer will draw the line.