Exercise 15 Page 298

By observing the given graph, we can see that the line passes through the points (- 4,- 2) and (4,4). 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 tell from the given graph that the rise, or change in y from left to right, is 6. We can also see that the run, or change in x from left to right, is 8. slope=rise/run ⇔ m=6/8 =3/4 We can confirm this answer by using the Slope Formula. m = y_2-y_1/x_2-x_1 Let's substitute (- 4,2) and (4,4) for (x_1,y_1) and (x_2,y_2), respectively.

m = y_2-y_1/x_2-x_1

SubstitutePoints

Substitute ( - 4,- 2) & ( 4,4)

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

SubNeg

a-(- b)=a+b

m=4+2/4+4

AddTerms

Add terms

m=6/8

ReduceFrac

a/b=.a /2./.b /2.

m=3/4

We obtained the same number as before. We can be sure the slope of the line is 34.