x²y²-x²-y²+1 x²-2x-4y²-4y
问题描述：
x²y²-x²-y²+1 x²-2x-4y²-4y
答
x²y²-x²-y²+1=(1-x²)(1-y²)
x²-2x-4y²-4y=(x-1)²-(2y+1)²=(x-2y-2)(x+2y)
答
x²y²-x²-y²+1
=(x²y-x²)-(y²-1)
=x²(y²-1)-(y²-1)
=(y²-1)(x²-1)
=(y+1)(y-1)(x+1)(x-1)
x²-2x-4y²-4y
=x²-4y²-2x-4y
=(x+2y)(x-2y)-2(x+2y)
=(x+2y)(x-2y-2)
答
x²y²-x²-y²+1 =x²(y²-1)-(y²-1)=(x²-1)(y²-1)=(x+1)(x-1)(y+1)(y-1)x²-2x-4y²-4y=x²-2x+1- (4y²+4y+1)=(x-1)²-(2y+1)²= [(x-1)+(2y+1)...