求y=(3x+3x+1)/(x+x-1)的值域?该怎样求,不是太明白,

y=(2x*x-2x+3)/(x*x-x+1),求值域? 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4) (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 求y=x（1-3x） (x y=(X+1)(X+2)(X+3)求导数 已知x(x-1)-(x²+y)=3 求x(x-y)+(y-x)的值 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y (-x+6):(x-y);(4x+y)=3;14:1,求x+y的值. 求值域 y=|x-1|-|3+x| 求值域y=|x-1|-|3+x| 用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+. 已知x(x+1)-(x²+y)=3求2/x²+y²-xy y=3x/(x平方+x+1)其中x小于0,求y的值域 求方程 dy/dx+x(y-x) +x^3(y-x)^2=1的通解~ 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值