Exercise 41 Page 338

Given a graph, can you think of two different ways to find the slope?

-7/8

Practice makes perfect

Observing the given graph, we can see that the line passes through the points (- 4,5) and (4,- 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 see that as the graph travels from left to right, the rise, or change in y, is -7. Similarly, the run, or change in x, is 8. slope=rise/run ⇔ m=-7/8=- 7/8 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 ( - 4,5) & ( 4,- 2)

m=- 2- 5/4-( - 4)

SubNeg

a-(- b)=a+b

m=- 2-5/4+4

AddSubTerms

Add and subtract terms

m=-7/8

MoveNegNumToFrac

Put minus sign in front of fraction