Question 110679
{{{3x-y=-7}}}
{{{x+y=-9}}}
:
Add the second equation to the first, term by term.
:
{{{4x=-16}}}
{{{x=-4}}}
:
Substitute -4 for x in either of the original equations.
:
{{{-4+y=-9}}}
{{{y=-5}}}
:
Check:
{{{3(-4)-(-5)=-7}}}, {{{-12+5=-7}}}, check
{{{-4-5=-9}}}, check