Answer:
I think 3x doesn't belong because it is the only positive number.
I think -5x doesn't belong because it is the only one without a 3.
I think -3 doesn't belong because it is the only one without an x.
I think -3x² doesn't belong because it is the only one with an exponent.
Step-by-step explanation:
Just use one of the ones above!
(hope this helps!)
