Exercise 19 Page 91

Observing the given graph, we can see that the line passes through the points (-2,3) and (2,1). 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, or change in y, is -2. Similarly, the run, or change in x, is 4. slope=rise/run ⇔ slope=- 2/4 = - 1/2 We can confirm this answer by using the other method, the Slope Formula. m = y_2-y_1/x_2-x_1 We will use the given points to solve for the slope. Note that it does not matter which point we choose to use for ( x_1, y_1) and ( x_2, y_2), since the result of using the Slope Formula will be the same.

A slope of m=- 12 means that for every 2 steps in the positive horizontal direction, the graph travels 1 step in the negative vertical direction.