Question 306818
{{{x+y+z=9}}}
{{{x-y-z=-7}}}
{{{x-y+z=1}}}
by now you should know the elimination method, because that is what u need to know to solve this problem, the first 2 equations are perfect, so lets add them together

{{{x+y+z=9}}}
{{{x-y-z=-7}}}solve for x
{{{2x+0+0=2}}}divide by 2
{{{x=1}}}
take the second 2 equations and solve for y
{{{x-y-z=-7}}}
{{{x-y+z=1}}}
_ _ _ _ _ _ _
{{{1-y-z=-7}}}
{{{1-y+z=1}}}add the equations together
{{{2-2y+0=6}}}
{{{-2y=4}}}
{{{y=-2}}}
_ _ _ _ _ _ _
{{{x+y+z=9}}}
{{{1-2+z=9}}}
{{{-1+z=9}}}
{{{z=10}}}

The solution set is [1,-2,10]