Answer: (4)
Explanation:
At step 2 the student rewrites 6 as 2*(4), and 8x as 2*(6x). This is incireect, since 2*(4) is actually 8, and 2*(6x) is 12x.
The correct way to do it is to rewrite 6 as 2*(3), and rewrite 8x as 2*(4x), which corresponds to the answer option (4)