Which could be the first step in solving the equation represented by the model below? 3 x tiles and 4 positive 1 tiles = 2 x tiles and 6 positive 1 tiles Add 4 negative unit tiles to both sides. Add 4 negative unit tiles to the left side, and add 6 negative unit tiles to the right side. Add 4 positive unit tiles to both sides. Add 6 negative unit tiles to the left side, and add 4 negative unit tiles to the right side.