Slopes of Parallel and Perpendicular Lines
Different Forms of a Linear Equation Standard Form Slope-Intercept Form Point-Slope Form Standard Form Slope-Intercept Form Point-Slope Form Ax + By = C where A, B, & C are real numbers and A & B are not both zero y = mx + b where m is the slope and b is the y-intercept y - y 1 =m (x - x 1 ) where m is the slope and (x 1, y 1 ) is a point on the line
Slope The slope of the nonvertical line through the points and is m = The slope of a vertical line is not defined. The slope of a horizontal line is zero. The slope of the nonvertical line through the points and is m = The slope of a vertical line is not defined. The slope of a horizontal line is zero.
Slope of Parallel and Perpendicular lines Two lines are parallel if and only if they have equal slopes. Two lines are perpendicular if and only if the product of their slopes is -1. Two lines are parallel if and only if they have equal slopes. Two lines are perpendicular if and only if the product of their slopes is -1.
Examples Find the slope of the line through the given points. a.(-4, 7) and (3, 7) b.(3, -1) and (3, 2) c.(1, -4) and (2, 5) d.(-2, 5) and (1, -1) Find the slope of the line through the given points. a.(-4, 7) and (3, 7) b.(3, -1) and (3, 2) c.(1, -4) and (2, 5) d.(-2, 5) and (1, -1)
Examples ANSWERS a. b. c. d. ANSWERS a. b. c. d.