因式分解：x² y²—x² -y² +1、、、x² -2x-4y² -4y、、、(x+1)(x+2)-x-10、a² -2ab+b² -3a+3b-10、、、x² -3xy-18y² -3x-9y、、、急要啊~各位哥哥姐姐们发发慈悲吧、、、、

x² y²—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)
(x+1)(x+2)-x-10、
=x²+3x+2-x-10
=x²-2x-8
=(x+2)(x-4)
a² -2ab+b² -3a+3b-10
=(a-b)²-3(a-b)-10
=(a-b+2)(a-b-5)
x² -3xy-18y² -3x-9y
=(x+3y)(x-6y)-3(x+3y)
=(x+3y)(x-6y-3)

x² y²—x² -y² +1=x²(y²-1)-(y²-1)=(x²-1)(y²-1）=(x+1)(x-1)(y+1)(y-1)x² -2x-4y² -4y=(x-2y)(x+2y)-2(x+2y)=(x+2y)(x-2y-2)(x+1)(x+2)-x-10=x²+3x+2...