Polynomials with Constants

I have a function with basically only 1 unknown, A but my function also contains other constants, B's & C's. Im after an solution for A in terms of B and C. I guess I just want to make A the subject.

My function is similar in nature to this;

A = [B/A + 2B/(A + C/2) + (A^2 + 3)/C] / [C^2 + 7A]

I understand how to use excel solver to solve higher order polynomials but not when the function also contains other constants . . . .

How can I solve this for A ? . . . with or without software.

I understand that there will probably be more than one solution for A. I am after the method rather than an actual answer to this problem.

Cheers.