作业帮x²-4y²-x+2y
(2x-y)²-4(x-y)(x+2y)
化简：（2x-y)²-4(x-y)(x+y)
（x-2y）²+（2x-4y)(x+y)+(x+y)²
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
[(y-2x)(-2x-y)-4(x-2y)²]*2y,其中x=1,y=2
(x+y)²+4(x+y)-5
若|x+2y-1|+y²+4y+4=0,求（2x-y）²-2（2x-y)(x+2y)+(x+2y)&
(3x-y)²-2x（4x-5y）-（x+2y）²
(x+y)和(x-y)各看成一个整体,合并同类项2(x+y)-3(x-y)²+3(x+y)+4(x-y)
已知x²+y²+5=2x+4y,求代数式（2x²-（x+y)(x-y))x((x+y-1)
多项式因式分解 1,(x-y)³-(x-y)²(x+y) 2,x(x²-xy)-(4x&#