Question

把多项式x^2-y^2-2x-4y-3因式分解

Answer 1

原式=x^2-y^2-2x-4y-4+1=(x^2-2x+1)-(y^2+4y+4)=(x-1)^2-(y+2)^2=[(x-1)+(y+2)][(x-1)-(y+2)]=(x+y+1)(x-y-3)所以,x^2-y^2-2x-4y-3=(x+y+1)(x-y-3)