Answer :

[tex]3a+2b=10 \\\\ a+b=10 \\\\ \boxed{a=10-b} \\\\ 3(10-b)+2b=10 \\\\ 30-3b+b=10 \\\\ -b=10-30 \\\\ -b=-20 \\\\ \boxed{b=20} \\\\ a=10-20 \\\\ \boxed{a=-10}[/tex]