{X-(X*15%+Y*30%)}/X-100%=45% 求X=?Y=?

x+x+x=15,x+y+y=19,求y-x等于几 二元函数f(x,y)=x+y/x-y,求f(y/x,x/y) x+x+x+y=52 y+y+y+x=36求x 已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x*x+y*y)(x*x+y*y)-(x*x+y*y)=12 求x*x+y*y等于多少 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!)+. 若x+7y=y-3x，求x y=ln(x^2+e^x) 求Y'X 求y=x^tanx+x^x^x的导数 求y'=y/(y-x) |x-y |=x-y |x |=1999 |y |2000,求x+y的值