计算:(3x^-1+3y^-1)÷(x^-2-y^-2)
(2x+y)(x+3y-1)计算
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8
计算:(-x-2y) * (3x-y)
[(2x+y)(x-3y)+y(x+3y)]÷(2x)计算,
计算:(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2
计算(x+y)(x+y)^2(-x-y)^3
1.计算(a^2+a+1)(a^2-a+1) 2.计算(x-y)(x+y)+(3x-2y)(2x+y)-x(6x-y)
已知x=2+根号3,y=2-根号3,计算代数式(x+y/x-y-x-y/x+y)乘以(1/x^2-1/y^2)
计算:1.(x-1)^2+2(1-x) 2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-
计算(1)x/x+y-x/x-y (2)a+2+4/a+2 (3)x^2-y^2/xy÷(x+y)
计算:(2/3x√9x+6x√y/x)+(y√x/y-√1/x)