You can put this solution on YOUR website! S=B+1/2Pc
solve for c
-------------
To "solve for" c means to get c on one side of the equal sign by itself.
S=B+1/2Pc
Subtract B from both sides
S-B = 1/2Pc
Multiply both sides by 2
2S-2B = Pc
Pc = 2S-2B
Divide by P
c = (2S-2B)/P
It's just a matter of moving things around. Carefully.