Exercise 25 Page 88

We can use the given table of values to graph the data on a coordinate plane. Then we can find the slope of the line that connects the points.

One way to use a graph to find the slope of a line is to count the change in the x -coordinates and the change in the y-coordinates.

We can see that as the graph travels from left to right, the rise, or change in y, is 80. Similarly, the run, or change in x, is 10. slope=rise/run ⇔ m=80/10=8 We can confirm this answer by using the other ratio from the Slope Formula. slope = y_2 - y_1/x_2-x_1 We will use the given points to find for the slope.

slope = y_2 - y_1/x_2-x_1

SubstitutePoints

Substitute ( 10,80) & ( 20,160)

slope=160- 80/20- 10

SubTerms

Subtract terms

slope=80/10

CalcQuot

Calculate quotient

slope=8

We obtained the same number as before. We can be sure the slope is 8. Now we can explain what the slope represents. A slope of 8 tells us that each ticket costs $8.