X+2Y-5=0 2Y+3Z-13=0 3Z+X-10=0 怎么解

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 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 若4x-3y-6z=0,x+2y-7z=0,求代数式5x*5x+2y*2y-z*z/2x*2x-3y*3y-10z*10 若{x+3y+10z=0 则 (x+y-z)/(x-y+z) 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, x+y-z=0 2x-3y+2z=5 x+2y-z=3 2x+5y+4z=0,3x+y-7z=0,则x+y-z=? 解方程组{2x+3y+z=11,x+y+z=0,3x-y+z=-2. 解三元一次方程：x+y-z=0,2x+y+z=7,x-3y+z=8 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y- 已知x+y-z=0,2x-y+2z=0 求（3x-2y+5z)/(5x-3y+2z)的值