Solve the equation by replacing x with -7 and then -1.
Then subtract the two to find the difference and divide that by the difference between -7 and -1.
f(-7) = -7^2 + 2(-7) -8 = 49 -14 -8 = 27
f(-1) = -1^2 + 2(-1) -8 = 1 -2 - 8 = -9
Difference between 27 and -9 = -36
Difference between -1 and -7 = -6
Rate of change = -36 /-6 = 6
