Question 862599
Multiply the first equation by 3 and add to the second.
{{{15x+3y+3x-3y=45+9}}}
{{{18x=54}}}
{{{x=3}}}
Then use either equation to solve for {{{y}}}
{{{3x-3y=9}}}
{{{x-y=3}}}
{{{3-y=3}}}
{{{y=0}}}