帮我做几个初2数学题.因式分解.

1：（2x+y）^2-（x+2y）^2
= (2x+y+x+2y)(2x+y-x-2y)
=(3x+3y)(x-y)
=3（x+y）(x-y)
2：4x^2（x-y）^2-6xy^2（y-x）
=(x-y)(4x^2 +6xy^2)
=2x(x-y)(2x+3y^2)
3：x^2-y^2+x+y
=(x+y)(x-y)+(x+y)
=(x+y)(x-y+1)