{x+y=16,y+z=20,z+x=18

(x+y-z)(x-y+z)= X+Y+Z=? 解方程组{x(x+y+z)=6,y(x+y+z)=12,z(x+y+z)=18 f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w) x+y+z=14,x'+y'+z'=15,(x-x')+(y+y')+z*z'=16,已知xyz为自然数,求x,y,z的 x y z x+y--- = --- = ---- ----y+Z z+x x+y ,求 z 的值 .求 x+y---- X+Y+Z=35 X/16+Y/10+Z/20=2.5 Z/16+Y/10+X/20=2.65怎么求x y z {x+z+y=15 z+x+w=18} {y+x+w=16 w+z+y=17} ,求x.y.z.w各是多少? 已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz 若z分之x+y+z=y分之x-y+z=x分之-x+y+z,求xyz分之(x+y)(y+z)(z+x) y+z÷x=Z+X÷y=X+Y÷z,X+Y+Z不等0求X+Y-Z÷X+Y+z值 (x+y-z)/z=(y+z-x)/x=(z+x-y)/y 求(x+y)(y+z)(z+x)/xyz