1. Slopes and Parallel Lines Goals: To find slopes of lines To identify parallel lines To write equations of parallel lines

2. Slope

3. Example Find the slope of A (2,3) and B (6,4).

4. Comparing Slopes of Lines Two non-vertical lines are parallel if and only if they have the same slope. Vertical lines are parallel. Are these lines parallel?

5. Equation of a line in slope-intercept form Slope-intercept form: Positive slope (the line rises from left to right) Negative slope (the line falls from left to right)

6. Examples Write an equation of a line passing through (2,3) having a slope of 5.

7. Equation of a horizontal and vertical line The slope of a horizontal line is zero. Why? The slope of a vertical line is undefined.Why?

8. Writing Equations Write an equation passing through (-4,3) and parallel to 1. Find the slope of a line that is parallel to this line. 2. Use this slope and the point given to find b. 3. Write the equation. What do the graphs of these equations look like?

9. Students Are lines l and p parallel?

10. Students 1. What is the equation of a line that passes through C(9,-2) that has a slope of 1/3? 2. Write an equation passing through (2,3) and parallel to