Question 173477
Eq. 1 {{{x-3y-z=-9}}}
Eq. 2 {{{-2x+y+2z=3}}}
Eq. 3 {{{2x+y+3z=8}}}


Add Eq. 2 to Eq. 3:


Eq. 4 {{{0x+2y+5z=11}}} → {{{2y+5z=11}}}


Multiply Eq. 1 by 2:


Eq. 5 {{{2x-6y-2z=-18}}}


Add Eq. 2 to Eq. 5:


Eq. 6 {{{0x-5y+0z=-15}}} → {{{y=3}}}


Substitute value for y in Eq. 4:


{{{2y-5z=11}}} →  {{{2(3)-5z=11}}} → {{{-5z=5}}} → {{{z=-1}}}


Substitute values for y and z in Eq. 1:


{{{x-3y-z=-9}}} → {{{x-3(3)-(-1)=-9}}} → {{{x-9+1=-9}}} → {{{x=-1}}}


So the solution set is the ordered triple ({{{-1}}},{{{3}}},{{{-1}}})