(49X^2-9Y^2)÷(7X-3Y)

计算(x-y)^7÷(y-x)^6+9-x-y)^3÷(x+y)^2 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x 计算：(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2 18(x+y)^8(x-y)^7÷[3(x+y)^3(x-y)^3]^2 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 化简3(x-y)-7(x--y)+2(y-x) (x+y)-(x-y)^3÷(x-y)(x+y)×2y化简e , 数学题求解解下列方程组x+y/2 +x-y/3=62(x+y)-x=-49x+7y=397x+9x=41 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 [(1/9(x+y)^3-2(x+y)^2-2/3(x+y)]÷x+y/3x+y/3x+y是整体.. [(x+2y)²-(x+y)(x-y)-7y²】÷（2y） x(x-y)2-(y-x)3 计算：1.（x-1)^2+2(1-x) 2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-2y/(x+y）1.（x-1)^2+2(1-x)2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-2y/(x+y） 计算:y×(y/x)^3÷[-(x^2)/y]^-2 [(2x+y)(x-3y)+y(x+3y)]÷(2x)计算, [(x-2y)²+(x+y)(3x-y)-3y²]÷2x化简。 4x-3y/x-2y÷6y-8x/y-2x