计算：(X+2y)^2 (x^2+4Y^2)^2 (X-2y)^2 -（x^4-2y^4)^2七点半之前我就要见到答案，否则我就惨了，大哥大姐们江湖救急啊

计算:2xy/(x+y)².(x+y)/4y 计算:y-x分之x+y+x-y分之y-y-x分之2x-y 计算2x/x-y 计算（2x-3y)(x+4y)-(3x+y)(x-2y)（2x-3y)(x+4y)-(3x+y)(x-2y) 计算:(x+2y)(2x-y) 计算:(x+3y)(2x-y) 计算:(2x-3y)(x+y) 计算:(-x-2y) * (3x-y) 计算：(x+y)-3(x-2y). (x-3y)(y+2x)-(4y-3x)(3x+4y)计算 计算:(x-y)^2*(x+y)^3*(-x-y)^3*(y-x)^4 计算：[（x+y）³-2(x+y)²-4(x+y)]÷（x+y) 计算[(x+y)的立方-2(x+y)的平方-4(x+y)]÷(-x-y) 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 计算：[(x+y)(x-y)-(x-y)^2+2y(x-y)]/(-2y) 计算:(x-y)^2*(y-x)^2*(x-y)^6 计算(x-y)(y^2-x^2)(-x-y) 计算(x+y)(x+y)^2(-x-y)^3