Distance / Rate = Speed...so
Jack's speed = Jill's speed
x^2 -11x - 22 = (x^2 - 3x - 54) / (x + 6)
x^2 - 11x - 22 = (x - 9)(x + 6) / (x + 6)
x^2 - 11x - 22 = x - 9 rearrange as
x^2 - 12x - 13 = 0 factor
(x - 13) ( x + 1) = 0
Set each factor to 0 and solve for x and we get that x = 13 or x = -1
Reject the second answer since itleads to a negative speed
If x = 13, the speed is 4 mph