Question 1054679
1.{{{2x + y- z = 5}}} 
2.{{{2x + 8y + 4z = 32}}} 
3.{{{30x + 12y -4z = 24 }}}
Multiply 1 by 4 and add to 2,
{{{8x+4y-4z+2x+8y+4z=20+32}}}
{{{10x+12y=52}}}
4.{{{5x+6y=26}}}
Add 2 and 3,
{{{2x+8y+4z+30x+12y-4z=32+24}}}
{{{32x+20y=56}}}
5.{{{8x+5y=14}}}
Multiply 4 by 5 and 5 by -6 and add together,
{{{25x+30y-48x-30y=130-84}}}
{{{-23x=46}}}
{{{x=-2}}}
Then,
{{{5(-2)+6y=26}}}
{{{6y=36}}}
{{{y=6}}}
and
{{{2(-2)+6-z=5}}}
{{{-4+6-z=5}}}
{{{-z=3}}}
{{{z=-3}}}