(x^2-3x)^2+4x^2-12x-21因式分解

问题描述:

(x^2-3x)^2+4x^2-12x-21因式分解

原式=(x^2-3x)^2+2*2*(x^2-3x)+4-25
= (x^2-3x+2)^2-5^2
= (x^2-3x+2-5)*(x^2-3x+2+5)
= (x^2-3x-3)*(x^2-3x+7)