若2x-3y-z=0 x+3y-14z=0 且z≠0 求(x^2+3xy)/(y^2+Z^2)的值给具体讲讲

若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 若x+y+z=3y=2z,则x/x+y+z=? 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) x+y+z=6 x+2y+3z=14 y+1=z 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 (1)X+Y=15,Y+Z=-6,Z+X=7.(2)X+Y=-14,Y+Z=-7,Z+X=9.(3)X+Y=0,Y+Z=-1,Z+X=-1. 2x+z=10 x+y-z=4 3x-y-z=0 如果2x-3y=z x+3y-14z=0 求x:y:z 快, 若方程组2x+3y-z=0,x-3y-z=0,则x：y：z=? 若方程组：x+y-2z=0,3x+y-z=0,则x：y：z= 若x/2=y/3=z/4不等于0,求x+y+z/x+y-z的值 若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z 若4x-3y-6z=0,x+2y-7z=0,则x+y+z/3x-y+z=? 若(4x-3y-3z)^2+|x-3y-z|=0 且xyz不等于0 则4x+y-z/x+y+z 的值 若{x+3y+10z=0 则 (x+y-z)/(x-y+z){2x-y-2z=0