Question 922760
Multiply the second equation by {{{-5}}} and add to the first to eliminate {{{x}}}.
{{{5x-7y-5x+20y=-12+15}}}
{{{13y=3}}}
{{{y=3/13}}}
Then use either equation to solve for {{{y}}}.
{{{5x-7(3/13)=-12}}}
{{{5x-21/13=-156/13}}}
{{{5x=(-156+21)/13}}}
{{{5x=-(135/13)}}}
{{{x=-(27/13)}}}