(x-3)(x-1)(x+2)(x+4）+24
=[(x-1)(x+2)]*[(x-3)(x+4)]+24
=(x^2+x-2)(x^2+x-12)-24
=(x^2+x)^2-14(x^2+x)-48
=(x^2+x-6)(x^2+x-8)
=(x-2)(x+3)(x^2+x-8)
(x^2-5x)(x^2-5x-2)-24
=(x^2-5x)^2-2(x^2-5x)-24
=(x^2-5x-6)(x^2-5x+4)
=(x-6)(x+1)(x-1)(x-4)