Answer:
1. 2x can be seen as +2x therefore when you put it as +2x-5x the answer will be - 3x
2. +3a+2a also equals +5a
3. - 5 is left alone and there is no other similar expression
Put them together the answer becomes
-3x+5a-5
It doesn't have to be the same order of format but the numbers must be as such