(x^2y^2)/(x^3+y^3)的在x,y都趋于0的重极限

已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 [(x+2y)(x-2y)-(2x-y)²+(3x-y(2x-5y)]/(-x)的解答 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 x(x-y)2-(y-x)3 (x+3y)的平方+2(x-y)(x+y)+(x-3y)的平方 2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方 y=3(x-y),x=2(x-y)求x,y的值 先化简,在求值,4(x+y)的平方-7(x+y)(x-y)+3(x-y)的平方,其中x=2,y=-7分之2 [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/【(x-y)/x】的负二次方 (x-y)X(2x-2y)的平方X(3x-3y)的平方 [(3x+y)(x-y)-(2x+3y)(x-y)]*(x-y) 计算：x+2y/x-y+2x/y-x-3y/x-y 化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方 ((x+y)/(x+y))的平方乘(2y-2x)/(3x+3y)-(x的平方)/(x的平方-y的平方)除以x/y