Your just combining like terms here!
By adding the you can just start by combining them with a plus sign. Like so:
3z - 4 + 2z + 5
Now you can combine terms with a z. So 3z and 2z which is 5z. So you can write this:
5z - 4 + 5
Now you have to combine the plain old numbers (but remember to take a look at the sign - or +) So -4 and + 5 which is +1 So this is your answer:
5z + 1
Hope that helps! Feel free to ask me if you have any questions! ^-^
- mathwizzard3
