Question 374903
1.{{{2A+B=42}}}
2.{{{A-B=-6}}}
Add the equations together,
{{{2A+B+A-B=42-6}}}
{{{3A=36}}}
{{{highlight(A=12)}}}
Then from eq. 2,
{{{12-B=-6}}}
{{{highlight(B=18)}}}