分解因式(x+y)(x-y)+4(y-1)

推荐回答

(x+y)(x-y)+4(y-1)=x²-y²+4y-4=x²-(y²-4y+4)=x²-(y-2)²=(x-y+2)(x+y-2)

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

=x^2-y^2+4y-4

=x^2-(y^2-4y+4)

=x^2-(y-2)^2

=(x+y-2)(x-y+2)