Answer:
B
Step-by-step explanation:
given
R = [tex]\frac{F}{N+F}[/tex] ( multiply both sides by N + F )
R(N + F) = F distribute parenthesis on left side
RN + RF = F ( subtract F from both sides )
RN + RF - F = 0 ( subtract RN from both sides )
RF - F = - RN ( multiply through by - 1 )
F - RF = RN ← factor out F from each term on the left side )
F(1 - R) = RN ← divide both sides by 1 - R
F = [tex]\frac{RN}{1-R}[/tex]
