Answer:
They subtracted 2x from both sides.
Explanation:
They removed 2x from each side because in order to find x it will have to be removed on one side. Since 2x - 2x = 0 it is 2x is out of the equation for the right side and on the left side -2x -(-4x) = -6x which means that there is one x variable left in the equation thus making it solvable.