Question 1053216
{{{F=3S}}}
Nine years ago,
{{{F-9=4(S-9)}}}
{{{F-9=4S-36}}}
{{{F=4S-27}}}
Substituting from above,
{{{3S=4S-27}}}
{{{-S=-27}}}
{{{S=27}}}
So,
{{{F=3(27)}}}
{{{F=81}}}