Question 369509
1.{{{x + y + z = 2}}}
2.{{{x + 2y - z = 5}}}
3.{{{3x - y = 16}}}
Add eq. 1 and 3 together,
{{{x+y+z+x+2y-z=2+5}}}
4.{{{2x+3y=7}}}
Multiply eq. 3 by 3 and add to eq. 4,
{{{9x-3y+2x+3y=48+7}}}
{{{11x=55}}}
{{{highlight(x=5)}}}
Then from eq. 3,
{{{15-y=16}}}
{{{highlight(y=-1)}}}
Then from eq. 1,
{{{5-1+z=2}}}
{{{highlight(z=-2)}}}