Which could be the first step in solving the equation represented by the model below? X X X x
II
O Add 4 negative unit tiles to both sides.
O Add 4 negative unit tiles to the left side, and add 6 negative unit tiles to the right side.
O Add 4 positive unit tiles to both sides.
O Add 6 negative unit tiles to the left side, and add 4 negative unit tiles to the right side.