[ (x-y)^3 × (√x+√y)^(-3) + 3(x√y-y√x) ] / (x√x+y√y)= [ (√x-√y)^3 + 3√xy × (√x-√y) ] / (x√x+y√y)= (x√x-y√y) / (x√x+y√y)这是正确的步骤跟答案.其中用到咯(a+b)^3 = a^3 + b^3 + 3ab(a+b)和a^3 + b^3 = (a+b)

先化简 再求值 (2x-y)(y+x)-(x-2y)(2y+x)-(-3y+x)^2其(√x+1)+y^2+4=-4y 完全立方公式[ (x-y)^3 × (√x+√y)^(-3) + 3(x√y-y√x) ] / (x√x+y√y) 　　=[ (√x-√y)^3 + 3√xy × (√x-√y) ] / (x√x+y√y) 　　=(x√x-y√y) / (x√x+y√y)什么意思,没看明白 已知：x*x+√3y=√5,y*y+√3x=√5,且x≠y,求 y/x+x/y 用logax、logay、loga(x+y)、loga(x-y)表示下列各式loga(x^3y/(x+y)^4)loga(√x/√y-√Y/√x) 若x>0,y>0,且√x(√x+√y)=3√y(√x+5√y),求2x+2√x*√y+3y/x-√x*√y+y y^2-2(√x+1/√x)y+3 (3x-y)(3y+x)-(x-y)(x+y) 已知√(y/x)+√(x/y)=3√2/2,那么y/x+x/y的值为 已知实数x,y,满足x-√x-1=√y+3-y,则x+y最大值是? 计算：｛x√x+x√y / xy-y²}-{x+√xy+y / x√x-y√y} 若x,y∈{-√3,-1,1,2},则(x,y)∈{(x,y)|x^2+y^2 √x+y-3+/xy+x+y-2/＝0,求x÷y+y÷x的值. ³√x+y=3,√x-y=2 求x,y的平方根 |x-2y|+√3x-4y =0求x y值 |2x+y+1|+√2y+3x=0则x.y= 解方程组x-y=6;√(3x/x-y)+3√[(x-y)/3x=4] √x(√x+2√y)=√y(6√x+5√y,求x-3√xy+2y/x+√xy-6y 已知实数x,y满足x²+√2 y=√3,y²+√2 x＝√3,则x/y+y/x=?