Hey there!
Let's combine like terms:
p-p-p-q-q-q
p-p-p=-p
-p-p-q-q-q
-p-3q
Remember, like terms are from the same "family"
So p's are from the p family, and q's are from the q family.
Hope everything is clear.
Let me know if you have any questions.
#LearningDoesn'tEnd