Helppppp plzxxxxxx i need to hand this in for my test

-17a +7b + 16ab

Step-by-step explanation:

look for all the number that have only a in them and then combine them

-9a - 8a

next look for all the ones that have only b in them and combine them as well

12b - 5b

Then look for any ab combinations to combine with other ab's since there is only one it will just be

16ab

so in the end, you have

-17a +7b + 16ab

When 2 triangle sides are known, the third side must be:
LESS than the sum of the other 2 sides and
GREATER THAN the difference of the other 2 sides
So, the third side must be greater than 3 and less than 11.

Source:
http://www.1728.org/trianinq.htm