Exercise 31 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. 2=3- r/3- 6 or 2=r- 3/6- 3 Here we will use the points in the given order and solve for the unknown coordinate.

When r=9, the line passes through both points.