Question 1208192
{{{system(3a+5b=3,a+2b=13)}}}


Elimination Method may be a good choice.


Multiply entire second equation by 3.

{{{system(3a+5b=3,3a+6b=39)}}}


From  this, add negative of first equation to second equation.
{{{(3a-3a)+(6b-5b)=39-3}}}
{{{0+b=236}}}
{{{highlight(b=36)}}}



This value for b could be used for substituting into the original second 
equation to find a.
{{{a+2b=13}}}
{{{a=13-2b}}}
{{{a=13-2*36=13-72}}}
{{{highlight(a=-59)}}}