Exercise 32 Page 81

The Slope Formula is used to determine the slope m of the line that connects two given points, ( x_1, y_1) and ( x_2, y_2). m=y_2- y_1/x_2- x_1In this case, however, we have been given the slope of a line and two points with a missing coordinate. When we substitute these values into the Slope Formula, it does not matter which point we choose to use as ( x_1, y_1) or ( x_2, y_2). Both will give the same result. 1/3=r- 1/5- 8 or 1/3=1- r/8- 5 Here we will use the points in the given order and solve for the unknown coordinate.

When r=0, the line passes through both points.