x+y=11y+z=9z+x=10求XYZ的值分别为多少

已知x+y+yz=5,y+z+xy=8,x+z+xy=9,求x,y,z 已知实数x,y,z,满足那么x+y=6,z^2=xy-9,求(x+y)^z 若xy-z=0,且(y+x)/x=(z+x)/y=(y+x)/z,求[(y+z)(z+x)(x+y)]/xyz的值? 若xy-z不等于0,且(y+x)/x=(z+x)/y=(y+x)/z,求[(y+z)(z+x)(x+y)]/xyz的值? z=f(x+y,xy,x/y),求z对于xy的二次导数 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 已知XY=2(X+Y),YZ=4(Y+Z),ZX=5(Z+X),求X,Y,Z已知XY=2(X+Y),YZ=4(Y+Z),ZX=5(Z+X),求X,Y,Z 若x-y=6,xy=-8,求代数式(x+y+z)²+(x-y-z)(x-y+z)-2·z(x+y)的值 若x+y=6,xy=-8,求代数式(x+y-z)^2+(x+y-z)(x+y+z)-2·z(x-y) 已知x-y=6,xy=-8,求代数式½(x+y+z)²+½(x-y-z)(x-y+z)-z(x+y) (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 已知实数x,y,z满足x=6-y,z^2-4z+4=xy-9,求x,y,z的值 已知实数x,y,z满足x=6-y,z^2-4z+4=xy-9,求x,y,z的值. 方程组xy/x+y=2 yz/y+z=4 zx/x+z=5 求x,y,z 已知X+Y+Z=a,XY+YZ+XZ=b,求X*X+Y*Y+Z*Z的值 z=f(x*x-y*y,e的XY次方)求Z对X偏导 Z对Y偏导 X+Y-Z=15 X+5Y+10Z=70 求：X、Y、Z 5y+3z=z 求x²-25y²+9z²-6xy