Question

The formula T = 1/f relates the period of a sound wave T to its frequency f. Solve this formula for f.

Answer 1

T = 1/f 
We solve for f. What we can do here is to get the reciprocal of both sides to get f: 
reciprocal of T: 1/T 
reciprocal of 1/f: f 
Therefore 
1/T = f, or 
f = 1/T

Answer 2

$T=\frac{1}{f}$

$multiply \space\ both \space\ sides \space\ by \space\ f$

$Tf=1$

$divide \space\ both \space\ sides \space\ by \space\ T$

$f=\frac{1}{T}$