What is the greatest common factor (GCF) of the numerator and denominator

of the rational expression below?

4x + 20

x2 + 2x - 15

A. x

B. x-3

C. x+5

D. 4

C

Step-by-step explanation:

x²+2x-15 = x²-3x+5x-15 = x (x-3) + 5 (x-3) = (x+5) (x-3)

or delta:

∆=2²-4*1 * (-15) = 4+60=64

√∆=8

x1 = (-2+8) / 2 = 3

x2 = (-2-8) / 2=-5

and 4x+20 = 4 (x+5)

The same is (x+5), so it is GCF. answer C