把(x+y)看做一项
3(x-y)^2-7(x-y)+8(x-y)^2+6(x+y)
=11(x-y)^2-7x+7y+6x+6y
=11(x-y)-x+13y
3(x-y)^2-7(x-y)+8(x-y)^2+6(x+y)
把(x+y)看做一项
3(x-y)^2-7(x-y)+8(x-y)^2+6(x+y)
=11(x-y)^2-7x+7y+6x+6y
=11(x-y)-x+13y
把(x+y)看做一项
3(x-y)^2-7(x-y)+8(x-y)^2+6(x+y)
=11(x-y)^2-7x+7y+6x+6y
=11(x-y)-x+13y