计算:1÷(x^-2 + y^-2)

计算:1÷(x^-2 + y^-2) 计算(x+y-1)^2 计算:y×(y/x)^3÷[-(x^2)/y]^-2 计算:2/x+1/(x-y) 计算：(x+y/x-y)÷(xy+x^2) 计算2x/x-y 计算：(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2 计算(x-y)^7÷(y-x)^6+9-x-y)^3÷(x+y)^2 [(2x+y)(x-3y)+y(x+3y)]÷(2x)计算, 计算[(x+2y)²-(x+y)(x-y)-5y²]÷(2x) 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) (x+y)(x-y)-(2x+y)(x-y+1)计算要过程 计算 （x-2y)^6÷（2y-x)^5 计算(x+y)立方÷(x+2y)立方 计算：1/x^2-y^2+2/(x-y)^2 计算：1/(x-y)+1/(2y-2x) 计算(2x+y+1)(2x+y-1)