Question

3r+n^2-r+5n= write in simplest form.

Answer 1

This equation in simplest form would be n^2+5n+2r

To get this you would do so:
3r+n^2-r+5n
3r-r+n^2+5n   REARRANGE so it is easier to simplify
2r+n^2+5n    SUBTRACT the r from 3r

n^2+5n+2r  REARRANGE again so it is in the correct order (numerical + alphabetical order) 

Answer 2

2r+5n^3 is the answer