Answer:
6x-7
Step-by-step explanation:
First add 12x and 6x to get 18x:
(1/3)(18x-21)
Multiply each term by 1/3 = Divide each term by 3
18/3=6 and 21/3=7, so
(1/3)(18x-21)=6x-7
The correct answer is 6x-7.
:)
