Who knew?

When calculating for gain in an audio amplifier stage that includes resistances in parallel, you have to take the reciprocal of the sum of the reciprocals of the individual resistors. Duh!

Hence, Gain=(75K OHMS)||(100K OHMS)||(1.47M OHMS)/(1/1400 uMHOS + 0 OHMS)=58.3

OR

Gain=(1/(1/75000+1/100000+1/1470000))/(1/.0014)=58.3