((м-в) : 5м) : ((м^2 - 64) : 15)

First, let's simplify the expression inside the first set of parentheses.

(m-в) : 5м can be simplified to (m - в) / 5м which is equal to (m - в) * (1 / 5м).

Next, let's simplify the expression inside the second set of parentheses.

(m^2 - 64) : 15 can be simplified to (m^2 - 64) / 15 which is equal to (m^2 - 64) * (1 / 15).

Therefore, the overall expression is:

(m - в) (1 / 5м) : (m^2 - 64) (1 / 15)

Now, we can simplify further if needed depending on the context in which the expression is being used.