Answer:
-m + 7n - 2
Step-by-step explanation:
[tex](-2m-3n-1)+(5m+3n+4)+(-4m+7n-5)=\\-2m-3n-1+5m+3n+4-4m+7n-5=\\-2m+5m-4m-3n+3n+7n-1+4-5=\\-m+7n-2[/tex]
