z=0.015x*x+y*x*0.05+(1-x-y)*2.5*(x+y) x>0.35.x

(x+y-z)(x-y+z)= f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w) X+Y+Z=? z/(x-y) × y/(x+y) 一条分式数学题已知x y z满足x/x+y + y/z+x + z/x+y =1,求x²/x+y + y&su x y z x+y--- = --- = ---- ----y+Z z+x x+y ,求 z 的值 .求 x+y---- 已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1 分解因式：（1):x(x-y)+y(y-X) 多项式(x+y-z)(x-y+z)-(y+z-X)(Z-x-y)的公因式是 已知 x/(y+z)+y/(z+x)+z/(x+y)=1 x+y+z=1 求xyz/(x+y)(y+z)(z+x)的最大值 {(x,y) |x|+|y| x>y?x:y