Honors Geometry Companion Book, Volume 1

3.2.3 Point-Slope Form Key Objectives • Graph lines using slope and a point. • Use point-slope form to graph. • Write linear equations in slope-intercept form. • Use two points to find intercepts. • Evaluate equations in slope-intercept form. Key Terms • The point-slope form of an equation of a line with slope m passing through ( x

1 , y 1 ) is y − y 1 = m ( x − x 1 ).

Example 1 Using Slope and a Point to Graph Use the following steps to graph a line given the slope and a point on that line. 1. Plot the point. 2. Starting from the point, use the slope (rise/run) to plot a second point. 3. Draw a line through the two points. Remember that if the slope of a line is an integer, then the run is 1. For example, if the slope of a line is 3, then the rise is 3 and the run is 1, because 3 = 3/1.


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