x² + 4x + 5x + 20
We can group this equation into two terms:
x² + 4x and 5x + 20
The greatest common factor of x² + 4x is x, and the gfc of 5x + 20 is 5, then:
x² + 4x = x(x + 4)
5x + 20 = 5(x + 4)
Replacing into the original expression,
x² + 4x + 5x + 20 =
= x(x + 4) + 5(x + 4) =
Taking (x + 4) as the gcf,
= (x + 4)(x + 5)
