12+n+n+n
2n+12+n
Let's look at each option and see if they can be manipulated into 3(n+4).
12+n+n+n
* TRUE. This can be changed into 12 + 3n and then the 3 can be factored out to get 3(4 + n). Finally, due to the commutative property of addition, we can swap the 4 and n to get 3(n+4).
3n+4
* FALSE. It looks like someone attempted to distribute the 3 in 3(n+4) and forgot to continue the distribution to the 4. So this is wrong.
3n-12
* FALSE. There's no negative term anywhere in 3(n+4), so that minus 12 doesn't make any sense.
2n+12+n
* TRUE. Combine the 2n and n terms to get 3n, so you now have 3n+12. Factor out the 3 and you get 3(n+4) and therefore this works.
