Question 265445
The given equations are,
7x+5y+z=0       ...(1)
-x+3y+2z=16     ...(2)  
x-6y-z=-18      ...(3)
(1)*2=> 14x+10y+2z = 0   ...(4)
(2)-(4)=> -15x-7y = 16   ...(5)
(1)+(3)=> 8x-y = -18     ...(6)
(6)*7=>   56x-7y = -126  ...(7)
(5)-(7)=> -71x = 142
          x = 142/(-71)
          x = -2
(6)=>    8*(-2)-y = -18
         -16-y = -18
         -y = -18+16
         -y = -2
          y = 2
(1)=> 7*(-2)+5*(2)+z = 0
      -14+10+z= 0
      -4+z = 0
       z = 4
Therefore the solution is, x= -2, y=2 and z= 4