p/q = f/q- f for f

[math_celebrity]

p/q = f/q- f for f

Isolate f in this literal equation.

Factor out f on the right side:
p/q = f(1/q - 1)

Rewriting the term in parentheses, we get:
p/q = f(1 - q)/q

Cross multiply:
f = pq/q(1 - q)

Cancelling the q/q on the right side, we get:
f = p/(1 - q)