Collecting like terms =>
[tex]\begin{gathered} (\frac{2m}{5}-\frac{3m}{5})\text{- }\frac{4}{5} \\ we\text{ can simplify the terms with m coefficient} \\ \frac{2}{5}m\text{ -}\frac{3}{5}m \\ =\text{ find the lowest common multiple of the denominator} \\ =\text{ lowest common multiple of 5 and 5 is 5} \\ =\text{ }\frac{2m\text{ - 3m}}{5} \\ \Rightarrow\text{ }\frac{-m}{5} \\ \\ \\ \end{gathered}[/tex][tex]\begin{gathered} \text{Then we will obtain} \\ \frac{-m}{5}\text{ -}\frac{4}{5} \end{gathered}[/tex]We may decide to further simplify the expression or leave the answer as it is shown above,
On simplification we will need to get the lowest common multiple of the denominator which is 5
[tex]\frac{-m}{5}\text{ -}\frac{4}{5}\Rightarrow\text{ }\frac{-m\text{ - 4}}{5}[/tex]