What is the greatest common factor of the numerator and denominator of the rational expression below? 5x-20/x^2-2x-8

Factories both equations:

5 (x - 4) / (x + 2) (x - 4)

Then take out the common brackets:

5 / x + 2

Minus 2 from both sides:

3 / x

If you are looking for the greatest common factor of the numerator and denominator, the answer would be (x - 4)