Alice was trying to solve the equation 4x + 21 = 7x -12. In one of her steps Alice thinks she made a mistake and got the wrong answer. If she made a mistake, what step did Alice make a mistake? Step 1: 4x + 21 = 7x -12 Rewrite the equation Step 2: 4x -7x +21 = 7x -7x -12 Inverse Operation Step 3: -3x +21 -21 = -12 +21 Inverse Operation Step 4: -3x = 9 Solve with Inverse Operation Step 5: x = -3