分解因式 x-y-x²+2xy-y²+2

分解因式 x-y-x²+2xy-y²+2
分解因式 x-y-x²+2xy-y²+2

分解因式 x-y-x²+2xy-y²+2
x-y-x²+2xy-y²+2
=-（x²-2xy+y²)+(x-y)+2
=-(x-y)²+(x-y)+2
=-[(x-y)²-(x-y)-2]
=-(x-y-2)(x-y+1)

原式=-](x²-2xy+y²)-x+y-2]
=-[(x-y)²-(x-y)-2]
=-(x-y-2)(x-y+1)

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

x－y－x^2+2xy-y^2+2=x－y－(x^2-2xy+y^2)+2
=(x-y)-(x-y)^2+2
=[1+(x-y)][2-(x-y)] (应用十字相乘法分解因式)
=(1+x-y)(2-x+y)。