(2x2-y2)-[2y2-(x2+2xy)]=______．

4x2-y2/x2-2xy+y2 +(2x-y)/2x2-2xy x2-2x+2y-y2因式分解 (x2-4y2)-(x+2y)因式分解 因式分解(x2-y2)-(x-y)2快 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） 已知实数x.y满足（x2+y2）（x2+y2-1）=2,求x2+y2的值 x2-2xy+y2=4 x2+y2-x-y=6 解不等式x2-2xy+y2=4 x2+y2-x-y=6 解不等式 已知x,y满足（x2+y2）(x2+y2-1)=2,则x2+y2的值为多少?x2,y2表示x和y的平方 因式分解 (x2-y2)2-8(x2+y2-2) (x2+2xy+y2)( x2-xy+y2)2 化简 (x2-2xy+y2)-(x2+2xy+y2)=什么 (x2+y2)(x2-xy+y2)-2x2y2因式分解 ( x2+xy+y2) ( x2+xy+2y2)-12y4 （x2+y2）2-（x2+y2）-6= (x2-y2)-4(2x2-3y) x2+y2+x+y=18 x2+y2-2x-4x=24 解方程组 x2-2xy+y2-9 y=x+√(1-x2) y2=x2+(1-x2)+2x√(1-x2)