M-(-a)m

The expression \( m - (-a)m \) can be simplified.

First, note that \( -(-a) \) is the same as \( +a \). Therefore, we can rewrite the expression:

\[ m - (-a)m = m + am \]

Now, we can factor out \( m \) from both terms:

\[ m(1 + a) \]

So, the simplified form of the expression \( m - (-a)m \) is

\[ m(1 + a) \]