COURSE 3 LESSON 3-3 Understanding Slope Using coordinates, find the slope of the line between P (–2, 3) and Q (–1, –1). slope = change in y change in x 3 – (–1) –2 – (–1) = Subtract the coordinates of point Q from the coordinates of point P. 4 –1 = or –4 Simplify. 3-3

COURSE 3 LESSON 3-3 Understanding Slope Find the slope of the line in the graph. Describe how one variable changes in relation to the other. slope = change in y change in x 75 – 25 300 – 100 = Use coordinates of two points. = 50 100 Subtract. Simplify. 1 4 = The cost increases by $25 for every 100 miles traveled. 3-3

COURSE 3 LESSON 3-3 Understanding Slope Find the slope of each line. State whether the slope is zero or undefined. a. line k b. line p slope = = 1 – (–3) 2 – 2 4 slope = = = 0 2 – 2 –2 – 3 –5 Division by zero is undefined. The slope of a vertical line is undefined. The slope of a horizontal line is zero. 3-3

COURSE 3 LESSON 3-3 Understanding Slope The data in the table below are linear. Use the data to find the slope. Then graph the data and the line. x –1 0 1 2 y –1 1 3 5 + 1 + 1 + 1 + 2 + 2 + 2 slope = = or 2 change in y change in x 2 1 3-3

Understanding Slope x 2 4 5 9 1. Find the slope of each line. COURSE 3 LESSON 3-3 Understanding Slope 1. Find the slope of each line. a. line s b. line t 2. The data in the table below is linear. Find the slope. x 2 4 5 9 y –6 –12 –15 –27 2 3 undefined –3 3-3