x + y = 95(0.4*x + 0.78*y)/95 = 0.6
二元函数f(x,y)=x+y/x-y,求f(y/x,x/y)
分式的加减:[(x/y-y/x)除以(x+y)+x(1/y-1/x)]除以1+x/y,其中x=5,y=2
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
有这样一道题:计算(x-y)[(x+y)(x+y)-xy]+(x+y)[(x-y)(x-y)+xy]的值,其中x=200
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
请问f(x+y,x-y)=x平方y+y平方,f(x,y)等于什么?
) y=cos(x-y)
x+y=5; x^y+y^x=17
因式分解下列式子:x(x-y)+y(y-x)=?
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
若3x=7y,则y分之x= ,x:(x:y)=
若3x=7y,则y比x= ,x:(x+y)=