We are given the equation,
t = m + cn
We are asked to rewrite the formula to determine the cost of a yearly membership, m.
To transform this into the desired formula we want, all we have to do is to simply transfer the factor cn from the right to the left.
During a transfer, the mathematical sign of a factor changes to the opposite, that is:
+ becomes - and - becomes +
In this case, since cn has a sign of +, it becomes – if we transfer it. Therefore
t – cn = m
or
m = t – cn (ANSWER)