2.2 Slope and Rate of Change, p. 75 x y (x1, y1)(x1, y1) (x2, y2)(x2, y2) run (x2 − x1)(x2 − x1) rise (y2 − y1)(y2 − y1) The Slope of a Line m = y 2 − y 1 x 2 − x 1 Let’s take 2 points on the coordinate plane.

Find the slope of the line passing through (2, 6) and (−3, 4). Example 1 m = y 2 − y 1 x 2 − x 1 = 4 − 6 −3 − 2

Classification of Lines by Slope x y Positive Slope Rises from left to right x y Negative Slope Falls from left to right x y Zero Slope Horizontal line x y Undefined or No Slope Vertical line

Find the slope for the line passing through the given points. Tell whether the line rises, falls or is horizontal or vertical. Undefined Horizontal Line Vertical Line Rises left to right. Falls left to right.

Tell which line is steeper.

Graph the following on the coordinate plane. x y Parallel lines have the same slope.

Graph the following on the coordinate plane. x y Perpendicular lines have slopes that are opposite reciprocals

Tell whether the lines are parallel, perpendicular, or neither.

Tell which the lines are parallel, perpendicular, or neither. 