Exercise 11 Page 298

By observing the given graph, we can see that the line passes through the points (0,2) and (2,- 2). One way to use a graph to find the slope of a line is to count out the change in x and y.

We can tell from the given graph that the rise, or change in y from left to right, is - 4. We can also see that the run, or change in x from left to right, is 2. slope=rise/run ⇔ m=- 4/2 =- 2 We can confirm this answer by using the Slope Formula. m = y_2-y_1/x_2-x_1 Let's use the given points to solve for the slope.

m = y_2-y_1/x_2-x_1

SubstitutePoints

Substitute ( 0,2) & ( 2,- 2)

m=- 2- 2/2- 0

AddSubTerms

Add and subtract terms

m=- 4/2

MoveNegNumToFrac

Put minus sign in front of fraction

m=-4/2

CalcQuot

Calculate quotient

m=- 2

We obtained the same number as before. We can be sure the slope of the line is - 2.