Question 312157
1.{{{3x+4y=-12}}}
2.{{{-x+y=5}}}
Multiply eq. 2 by 3 and add them together,
{{{3x+4y-3x+3y=-12+15}}}
{{{7y=-3}}}
{{{y=highlight_green(-3/7)}}}
Then from eq. 2,
{{{-x+y=5}}}
{{{-x+3/7=5}}}
{{{-x=35/7-3/7}}}
{{{highlight_green(x=32/7)}}}