Exercise 5 Page 286

Observing the given graph, we can see that the line passes through the points (-3,1) and (- 1,- 4). 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 see that as the graph travels from left to right, the rise, or change in y, is - 5. Similarly, the run, or change in x, is 2. slope=rise/run ⇔ m=- 5/2=- 5/2 We can confirm this answer by using the Slope Formula. m = y_2-y_1/x_2-x_1 We will use the given points to solve for the slope.

m = y_2-y_1/x_2-x_1

SubstitutePoints

Substitute ( - 3,1) & ( - 1,- 4)

m=- 4- 1/- 1-( - 3)

SubNeg

a-(- b)=a+b

m=- 4-1/- 1+3

AddSubTerms

Add and subtract terms

m=- 5/2

MoveNegNumToFrac

Put minus sign in front of fraction

m=- 5/2

We obtained the same number as before. We can be sure the slope is - 52.