Factor in quadratic form.

x^{2}(x + 2) - (x + 2)

Notice that there is a greatest common factor (gcf) that you can factor out of the entire equation, that being: x + 2

x^{2}(x + 2) - 1(x + 2) ==> (x + 2) ( x^{2}(1) - 1(1) ) ==> (x + 2)(x^{2} - 1)

Thus, x^{2}(x + 2) - (x + 2) = (x^{2} - 1)(x + 2)