Question

Which of the following is a factor of both

X^2-2x-3 and x^2-5x-6?

Answer choices:
A. X-3
B. X+3
C. X-1
D.x+1

Answer 1

X^2-2x-3 = (x - 3)(x + 1)
x^2-5x-6 = (x - 6)(x + 1)

answer
D.x+1

Answer 2

x^2-2x-3

x^2+x-3x-3

x(x+1)-3(x+1)

(x-3)(x+1)

...

x^2-5x-6

x^2+x-6x-6

x(x+1)-6(x+1)

(x-6)(x+1)

So the common factor is (x+1)