If you've been stuck, I'll take the time to really explain it.
Part of simplifying expressions means collecting like bases. Like bases are 2+ terms that share the same base, so like x, or x^3, or 4x^2.
Let's look at your expression.
There are two obvious like bases, which is m, and 5.
4(m)
-3(m)
5
However, there are two terms with the base m, so they are like bases.
You can collect them like so.
4m - 3m = m
and therefore,
4m + 5 - 3m
(4m-3m) + 5
m + 5
Because it cannot be simplified further, the final result is m + 5
