The solving of the equation starts with:
6 x + 10 = 2 x - 2
in the second step the person made a mistake when trying to isolate the term in x on the right.
In order to get rid of the term "-2" on the right, one needs to ADD to both sides "2", therefore obtaining:
6 x + 10 + 2 = 2 x
and the combining of 10 + 2 is 12 (not 8 as the person mistankenly wrote)
the correct second step should have been:
6 x + 12 = 2x