How Amplitude modulation achieved?

How Amplitude modulation achieved?
The frequencies of two sidebands in an am wave are 640 KHz and 660KHz respectively. Find the frequencies of carrier and modulating signal. What is the bandwidth required for amplitude modulation?

In amplitude modulation, the amplitude of the carrier wave changes in according to the information which is to be sent.
At the transmitter end the low frequency modulating signals are superimposed on high-frequency carrier wave
at the receivers end the information which is received will change in amplitude according to the biasing voltage
upper side of band
fm+fc = 660 kHz
lowers side of band
fc-fm = 640 kHz
fc=650 kHz
fc+fm =660kHz
fm = 660 - 650=10 kHz
Bandwidth = upper side - lower side= (fm+fc)-(fc-fm )=2fm =2x10 kHz