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(x2-y2)-3 (2x2-3y2)
x2-y2=(x+y)·( ).
x2-y2=25,则(x-y)2(x+y)2=( )
把x2-y2-2y-1分解因式结果正确的是( )。
A.(x+y+1)(x-y-1) B.(x+y-1)(x-y-1)
C.(x+y-1)(x+y+1) D.(x-y+1)(x+y+1)