(x+y)(x-y)+4(y-1)
因式分解
(x+y)(x-y)+4(y-1)
因式分解
(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)
x^2-y^2+4y-4
=x^2-(y^2-4y-3-1)
=x^2-(y^2-4y-3)+1
=x^2-(y-3)(y-1)+1
(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)