Answer:
no
Step-by-step explanation:
I say that because one input is supposed to have only one output but (1,4)
(1,2) they have one input but two different outputs so it is not a function
The correct answer is option 4: 
Step-by-step explanation:
Given expression is:

The associative property states that for any three terms that are being multiplied, different order of multiplication (i.e. which two terms are multiplied first) will give the same answer.
Let a,b and c be the three terms
then

So applying the associative property on given expression

Hence,
The correct answer is option 4: 
Keywords: Associative property, Properties
Learn more about associative property at:
#learnwithBrainly
All you need to do it combine like terms.
3x + 9 + 4x + x
(3x + 4x + x) + 9
8x + 9
i hope this was helpful for you!