Question 368368
{{{4x+8y-4z=4}}}
1.{{{x+2y-z=1}}}
2.{{{3x+8y+5z= -11}}}
3.{{{-2x+y+12z= -17}}}
Multiply eq. 1 by (-3) and add to eq. 2,
{{{-3x-6y+3z+3x+8y+5z=-3-11}}}
{{{2y+8z=-14}}}
4.{{{y+4z=-7}}}
Multiply eq. 1 by (2) and add to eq. 3,
{{{2x+4y-2z-2x+y+12z=2-17}}}
{{{5y+10z=-15}}}
5.{{{y+2z=-3}}}
Subtract eq. 5 from eq. 4,
{{{y+4z-y-2z=-7-(-3)}}}
{{{2z=-4}}}
{{{highlight( z=-2)}}}
Then from eq. 4,
{{{y-8=-7}}}
{{{highlight( y=1)}}}
Then from eq. 1,
{{{x+2+2=1}}}
{{{highlight( x=-3)}}}