Factor x^2-2x-8=0 to find the solutions to the equation.

x=4    x=-2

Step-by-step explanation:

x^2-2x-8=0

What 2 numbers multiply to -8 and add to -2

-4*2 = -8

-4+2 = -2

(x-4) (x+2) =0

Using the zero product property

x-4 =0     x+2 =0

x-4+4=0+4    x+2-2=0-2

x=4    x=-2

the answer is 31.27mph