1. Equations of Lines Part 2 Students will: Write slope intercept form given a point and a slope 1

2. Example 1 Find the equation of a line (slope-intercept form) passing through point (2, -3) with slope of -5 y = mx + b What we Know: x = 2 y = -3 m = -5 Finding b: y = mx + b -3 = -5(2) + b -3 = -10 + b 7 = b Therefore: y = -5x + 7 2

3. Example 2 Find the equation of a line (slope-intercept form) passing through point (4, -1) with slope of 7 y = mx + b What we Know: x = 4 y = -1 m = 7 Finding b: y = mx + b -1 = 7(4) + b -1 = 28 + b -29 = b Therefore: y = 7x – 29 3

4. Example 3 Find the equation of a line (slope-intercept form) passing through point (-5, -3) with slope of 9 y = mx + b What we Know: x = -5 y = -3 m = 9 Finding b: y = mx + b -3 = 9(-5) + b -3 = -45 + b 42 = b Therefore: y = 9x + 42 4

5. Example 4 Find the equation of a line (slope-intercept form) passing through point (1, -2) with slope of 3 y = mx + b What we Know: x = 1 y = -2 m = 3 Finding b: y = mx + b -2 = 3(1) + b -2 = 3 + b -5 = b Therefore: y = 3x – 5 5

6. Using Point Slope Form y – y 1 = m(x – x 1 ) 6

7. Example 5 Find the equation of a line (slope-intercept form) passing through point (1, -2) with slope of 3 y – y 1 = m(x – x 1 ) Point Slope Form y – (-2) = 3(x – 1) Plug in values y – (-2) = 3(x – 1) Plug in values y + 2 = 3x – 3 Use distributive Property y + 2 = 3x – 3 Use distributive Property y = 3x – 5 Subtract 2 y = 3x – 5 Subtract 2 7

8. Example 6 Find the equation of a line (slope-intercept form) passing through point (3, 5) with slope of 6 y – y 1 = m(x – x 1 ) Point Slope Form y – 5 = 6(x – 3) Plug in values y – 5 = 6(x – 3) Plug in values y – 5 = 6x – 18 Use distributive Property y – 5 = 6x – 18 Use distributive Property y = 6x – 13 Add 5 y = 6x – 13 Add 5 8

9. Example 7 Find the equation of a line (slope-intercept form) passing through point (-3, 5) with slope of -2 y – y 1 = m(x – x 1 ) Point Slope Form y – 5 = -2(x – (-3)) Plug in values y – 5 = -2(x – (-3)) Plug in values y – 5 = -2(x + 3) Rewrite as y – 5 = -2(x + 3) Rewrite as y – 5 = -2x – 6 Use distributive Property y – 5 = -2x – 6 Use distributive Property y = -2x – 1 Add 5 y = -2x – 1 Add 5 9

10. Example 8 Find the equation of a line (slope-intercept form) passing through point (7, 8) with slope of -2 y – y 1 = m(x – x 1 ) Point Slope Form y – 8 = -2(x – 7) Plug in values y – 8 = -2(x – 7) Plug in values y – 8 = -2x + 14 Use distributive Property y – 8 = -2x + 14 Use distributive Property y = -2x + 22 Add 8 y = -2x + 22 Add 8 10