x-5y-3z=0 y+z-3x=3 x+y+3z=14 y+4z=3 z+x-3y=5 2x+y+z=7 2x-z=1 x+y-3z=6 3x+y+2z=11三元一次方程（上面的打错了）x-5y-3z=0 y+4z=3 2x-z=1y+z-3x=3 z+x-3y=5 x+y-3z=6x+2y+3z=14 2x+y+z=7 3x+y+2z=11

已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z 已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 x/2=y/3=z/5 x+3y-z/x-3y+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) 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 已知z、y、z同时满足x+3y-5z=0,2x-y-3z=0,求x:y:z 2x+z=10 x+y-z=4 3x-y-z=0 (x+y):(y+z):(z+x)=3:4:5 3x+y-z=-4已知(x+y):(y+z):(z+x)=3:4:5 ；3x+y-z=-4求x y z 方程组 (1) x+2y-3z=12 x-3y+2z= - 13 x-y-z=0 (2) x+ y=z 5x-y+z=18 2x+5y+3z= -1 三元一次方程：x+y-z=0 x+2y+z=13 2x-3y+2z=5x+y-z=0 x+2y+z=13 2x-3y+2z=5 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 解二元一次方程X+Y-5Z=0,3X-3Y-Z=0,求X:y:z x+y-z=0 x+2y-z=3 2x-3y+2z=5 x+y-z=0 2x-3y+2z=5 x+2y-z=3