怎么算3X+2Y+Z已知;XY/X+Y=1 ZY/Z+Y=2 ZX/Z+X=3 求3X+2Y+Z的值"/"是分数线或是说XY/(X+Y).......hurry up,dude

已知4x-3y=6z 2x+4y=14z 求2xy/x^+y^ 已知4x-3y=6z 2x+4y=14z 求2xy/x^+y^ 已知3x－y+2z=x+2y+3z=0,求（3x^－xy+2y^)/(2x^+4xy+y^)值? 已知XY+X/X+Y+1=2 XZ+2X/X+Z+2=3 (Y+1)(Z+2)/Y+Z+3=4 求X+Y+Z的值已知(XY+X)/(X+Y+1)=2 (XZ+2X)/(X+Z+2)=3 [(Y+1)(Z+2)]/(Y+Z+3)=4 求X+Y+Z的值 已知（x+y-xy）/(x+y+2xy)=(y+z-2yz)/(y+z+3yz)=(z+x-3zx)/(z+x+4zx),且2/x=3/y-1/z,则xyz=? 已知xy/x+y=3,yz/y+z=2,zx/z+x=1,求y的值 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 已知实数x,y,z,满足那么x+y=6,z^2=xy-9,求(x+y)^z 已知x,y,z∈R,求证:x^2+y^2>=xy+x+y-1 已知2x-3y-z=0,x+3y-14z=0(z≠0),求x^2+3xy／y^2+z^2 已知2x-3y-z=0 x+3y-14z=0(z≠0) 求x^+3xy/y^2+z^ 已知,xy/(x+y)=1,zy/(z+y)=2,zx/(x+z)=3,球x=? 已知xy/(x+y)=1,yz/(y+z)=2,zx/(z+x)=3,求x的值 已知1=xy/x+y,2=yz/y+z,3=xz/x+z,求 X的值 已知1/x=5/y+z=3/z+x 求2xy/yz ÷x/Y的值 怎么算3X+2Y+Z已知;XY/X+Y=1 ZY/Z+Y=2 ZX/Z+X=3 求3X+2Y+Z的值/是分数线或是说XY/(X+Y).......hurry up,dude 已知实数x,y,z满足x+y=5,z^2=xy+y-9,那么x+2y+3z=?我很着急 已知实数x.y.z满足x+y=5及z的2次方=xy+y-9则x+2y+3z=?