(x根号x+x根号y)/(xy-y^2)-(x+根号xy +y)/(x根号x+y根号y)(x根号x+x根号y)/(xy-y^2)-(x+根号xy +y)/(x根号x+y根号y) 累啊~~不会啊~~~哪位仁兄帮忙解下A ~~~~
(x√x+x√y)/(xy-y^2)-[x+√(xy)+y]/(x√x-y√y)???
,,,,,,,,,,,,,,,,,,,,,立方差公式a^3-b^3=(a-b)(a^2+ab+b^)
=x(√x+√y)/[y(x-y)]-[x+√(xy)+y]/{(√x-√y)[x+√(xy)+y]}
=x/[y(√x-√y)]-1/(√x-√y)
=(x-y)/[y(√x-√y)] 平方差:a^2-b^2=(a-b)(a+b)
=(√x+√y)/y。