Answer:
Amplifier gain is equal to 10.67.
Step-by-step explanation:
Voltage gain of an amplifier can be expressed as this equation:
A_v = (V_output) / (V_input)
Where A_v is the gain, V_output is the output voltage, and V_input is the input voltage.
For this we will solve:
A_v = 128 mV / 12 mV
A_v = 10.67
So the amplifier's gain is 10.67.
Cheers.