Question 881527
{{{3(x+y)=7(y-x)}}}
{{{3x+3y=7y-7x}}}
{{{10x-4y=0}}}
1.{{{5x-2y=0}}}
.
.
.
{{{5(3x-y)=x+3}}}
{{{15x-5y=x+3}}}
2.{{{14x-5y=3}}}
Multiply eq. 1 by 5 and eq. 2 by 2 and subtract.
{{{25x-10y-(28x-10y)=0-6}}}
{{{-3x=-6}}}
{{{x=2}}}
Then,
{{{5(2)-2y=0}}}
{{{2y=10}}}
{{{y=5}}}