m-7n-12m+8n+7m

To simplify the expression \( m - 7n - 12m + 8n + 7m \), you can combine like terms.

1. Combine the \( m \) terms:

   • \( m - 12m + 7m = (1 - 12 + 7)m = -4m \)

2. Combine the \( n \) terms:

   • \( -7n + 8n = ( -7 + 8)n = 1n = n \)

Now, put the simplified terms together:

\[ -4m + n \]

So, the simplified expression is:

\[ -4m + n \]