What is the answer when you multiply 4e^-2x * e^-2x

This has confused me and i would be very grateful if someone could please answer it. Thanks.

4e^-4x

First put aside the 4.
e^-2x*e^-2x. Remember when you multiply, the powers get added together to give us e^-4x. Then put the 4 back into the equation.
_

when multiplying a common number raised to some powers, you add the powers up....remember you can only do this when the number (e here) is common....

so the product is

4 times e^(-2x) times e^(-2x)
= 4 times e^(-2x + -2x)
=4*e^(-4x)

4e^(-2x) * e^(-2x)

→ 4e^(-2x + -2x)

→ 4e^(-4x)

4 e^(-4x)

4
-----
e^(4x)