Exercise 9 Page 194

Observing the given graph, we can see that the line passes through the points (-3,4) and (3,-1). 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 (change in y) is -5. Similarly, the run (change in x) is 6. slope=rise/run ⇔ m=-5/6=- 5/6 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 ( -3,4) & ( 3,-1)

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

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Simplify right-hand side

SubNeg

a-(- b)=a+b

m=-1-4/3+3

AddSubTerms

Add and subtract terms

m=-5/6

MoveNegNumToFrac

Put minus sign in front of fraction

m=-5/6

Given that we obtained the same number as before, we can be sure the slope is - 56.