1. 2-4 Writing Linear Equations Objectives Students will be able to: 1) write an equation of a line given the slope and a point on the line, or two points on the line 2) write an equation of a line parallel or perpendicular to a given line

2. We can write a linear equation given any of these situations about the line: 1) we have the slope and y-intercept 2) we have the slope and one point on the line 3) we have two points on the line 4) we have a point on the line and we know our line is parallel to a particular line 5) we have a point on the line and we know our line is perpendicular to a particular line

3. We utilize the slope-intercept form of an equation when writing linear equations. To write a linear equation: –1–1) take the information given in the problem and substitute into y = mx + b –2–2) solve for b –3–3) substitute the m and b values back into y=mx+b

4. Example 1: Write an equation in slope-intercept form for the line with the following characteristics: a)Slope -2 and passes through (0, 7)

5. You try:

6. d) Passes through (2, -3) and (-3, 7)

7. You try. e) Passes through (6, 1) and (8, -4)

8. Parallel and Perpendicular Lines What do you notice about the slopes of these parallel lines? Parallel lines have the same slope.

9. Parallel and Perpendicular Lines What do you notice about the slopes of these perpendicular lines? Perpendicular lines have opposite sign, reciprocal slopes.

10. Example 2: Write an equation in slope-intercept form for the line that satisfies each set of conditions. a) Passes through (1, -3); parallel to the graph of y = 2x - 1

12. You try.