Is this equation true or false? Why? 20-4�ã2=16�ã2

With like radicands should I add the 4 to the other side of the equation? I'm really lost. Can someone please explain this to me?

20 - 4√2 = 16√2

is false.
The distibutive property of multiplication applies when there is a common factor (√2), such as:
20√2 - 4√2 = 16√2
or
(20-4)√2 = 16√2