Question 1191811
No matter any explanation


{{{system(-x+2y=1,-2x-3y=-12)}}}


{{{system(-x+2y=1,2x+3y=12)}}}


{{{system(-2x+4y=2,2x+3y=12)}}}


Sum the two equations.
{{{7y=12}}}
{{{highlight(y=2)}}}
-
{{{-x+2y=1}}}
{{{x-2y=-1}}}
{{{x=2y-1}}}
{{{x=2*2-1}}}
{{{highlight(x=3)}}}