1. Geometry Section 3.7 cont. “Writing Equations of Lines”

2. While the slope-intercept form for the equation of a line is very useful in graphing, it is not nearly as useful for writing the equation of a line (unless you happen to be given the slope and the y- intercept).

3. The point-slope form for the equation of a line is __________________ In this equation m is, again, the slope and x 1 and y 1 are ______________________

4. Example: Write an equation for the line in point-slope form. 1. slope of -1 and contains the point (-3, 9)

5. Example: Write an equation for the line in point-slope form. 2. passes through the points (1, 4) and (-3, 8)

6. Example: Write an equation for the line in point-slope form. 3. slope of 3 and a y-intercept of 15

7. Example: Write an equation for the line in point-slope form. 4. passes through the point (5, 1) and is perpendicular to the line