Factor completely

x(x+1)^2-4(x+1)

(2x+3)^2-9

x(x+1)(x+1) - 4(x+1)

[x(x+1) - 4](x+1)
(x^2 + x - 4)(x+1)
?

a^2-b^2 = (a+b)(a-b)
(2x+3 + 3)(2x+3 - 3)
(2x+6)(2x)
4(x+3)(x)
4x(x+3)