Question 452667
Let x = # of gallons of gasoline when tank is full.

==>  {{{(7x)/8 - 12 = x/2}}}

==> {{{(7x)/8 - x/2 = 12}}}

==> {{{(3/8)x = 12}}}
==>{{{ x = (8*12)/3 = 32}}} gallons.