Question 1058288
Write your equation with the necessary care.  c=ad/a+12  would be the same as the rendered form, {{{c=ad/a+12}}} which simplifies to {{{c=d+12}}} and this is not what you really have.


Your equation must use correctly placed grouping symbols:  c=ad/(a+12)  which will properly show as  {{{c=ad/(a+12)}}}.


The question requires solving the equation, or formula, for a in terms of c.