How do you find the value of r so the line that passes through each pair of points has the given slope.

You have two points, which can be labeled (x_{1,} y_{1}) and (x_{2}, y_{2}).

The formula for the slope between two points is m = (y_{2} - y1 )/(x_{2} - x_{1}).

We can fill in the pieces:

1/2 = (7 - r)/(6 - (-2))

0r (7 - r)/(6 + 2) = 1/2

(7 - r)/8 = 1/2

Now multiply both sides by 8 to clear 8 from the denominator on the left:

(7 - r) = 8(1/2)

7 - r = 4

**r = 3**