1. Module 5 Topic 2 More – Parallel and Perpendicular Slopes

2. Example 1 Write the equation of a line in slope-intercept form that is parallel to y = -4x + 3 and passes through (8, -8). y = -4x + 3 the slope is -4 so the perpendicular slope is 1/4. y = mx + b -8 = 1/4(8) + b -8 = 2 + b -10 = b y = 1/4x - 10

3. Example 2 Similar Problem: Write the equation of a line in slope-intercept form that is parallel to 3x + y = 9 and passes through (0, 4). 3x + y = 9 (solve for y). y = -3x + 9 slope is -3 so the parallel slope is also -3. y = mx + b 4 = -3(0) + b 4 = b y = -3x + 4

4. Example 3 Similar Problem: Write the equation of a line in slope-intercept form that is perpendicular to y = -3/4 x + 3 and passes through (18, -6). y = -3/4 x + 3 slope is -3/4 so the perpendicular slope is 4/3 y = mx + b -6 = (4/3)(18) + b -6 = 24 + b -30 = b y = 4/3 x - 30

5. Example 4 Similar Problem: Write the equation of a line in slope-intercept form that is perpendicular to 4x + 3y = 12 and passes through the point (5, 0). 4x + 3y = 12 (solve for y) 3y = -4x + 12 y = -4/3 x + 4 slope is -4/3 so the perpendicular slope is 3/4 y = mx + b 0 = (3/4)(5) + b 0 = 15/4 + b -15/4 = b y = 3/4 x - 15/4