已知2x-3y+z=0 求2x^2+3xy-9y^2+z^2+3xz 的值

已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知:2X-3y+2z=0,x+4Y-9/2z=0求:X:Z的值.X:y:Z的值.X+2y+X/X+y+Z的值. 已知:2X 已知 3x-y+2z=0 2x+y-3z=0,求x :y :z. 已知（1）X-Y+Z=0 (2)X+2Y-3Z=0 求X:Y:Z 已知｛2x-y-z=0,3x-9y+z=0求1,x:y:z 已知{x-5y+2z=0 3x-5y-4z=0,求x：y:z 已知｛X-Y+Z=0,X+2Y-3Z=0求X：Y：Z的值 已知{x-y+z=0,x+2y-3z=0},求x:y:z 已知：x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值. 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知有理数x,y,z满足 (x-1)(x-1)+|2x-y|+|x-3z|=0 求x+y+z的值,要过程! 已知有理数x,y,z满足 (x-1)(x-1)+|2x-y|+|x-3z|=0 求x+y+z的值 已知x+y-z=0,2x-y+2z=0 求（3x-2y+5z)/(5x-3y+2z)的值 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z 已知x+4y+3z=3x-2y-5z=0,求x+2y-z/2x-3y+7z的值 已知方程组{2x-3y+z=0 且x*y*z不等于0 求 x：y：z {3x-2y-6z=0 已知4X-3y-3z=0 X-3y-Z=0求3X-2Z+Y/-x+y+Z的值