Question

Can you add a negative and a positive when doing like term

Answer 1

Yes, you can add a negative and a positive when doing like terms.

Answer 2

In short yes. But to know for sure you can combine any term no matter the sign as long as they have the same type of variable attached to them for example

$x {}^{2} + x$
this cannot be combined because one is squared the other isn't
$x + - x$
you can combine these because they're the same type of variable this just becomes 1
$x + 3 + - 5$

we cant combine x into these because it's not just a constant number but we can combine 3 and negative 5 to get
$x - 2$

hope this helps!