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计算:(x-y)(1/9x-y)-(1/3x-y)(1/3x+y)
计算:(2/3x√9x+6x√y/x)+(y√x/y-√1/x)
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3x[xy-2x(1/y-x/3]+3y(x²-y²)
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
(2x+y)(x+3y-1)计算
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)
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)
因式分解 (1)6(x-y)^3-3y(y-x)^2 (2)x(x-y)(a-b)-y(y-x)(
1、x(x-y)(x+y)-x(x+y)^2
数学用乘法公式计算(x+y+1)(x+y-1)(2x-y-3)²
计算:1.(x-1)^2+2(1-x) 2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-