x+2z=3 2y+z=7 2x-y-z=-5怎么解?

{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x/2=y/3=z/5 x+3y-z/x-3y+z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) matlab解方程怎么出错了[x,y,z]=('x^2-5*y^2+7*z^2+12=0 ','3*x*y+x*z-11 解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3 解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3 解方程组2x+y-z=7 x+y+z =1 2x-y-z=5 解方程：{2x+3y+z=7,x+y+z=4,3x+y-z=-4 2x+4y+3z=9 3x-2y+5z=11 5x-6y+7z=13 这个方程怎么解? 解三元一次方程：x+y-z=0,2x+y+z=7,x-3y+z=8 三元一次方程组y-3x-2z=1 x+2y+3z=9 5x-7y+z=34怎么解 X-7Y+3Z=17和5X-6Y-Z=24和3X+7Y-2Z=1怎么解?