Multiple choice What must be subtracted from 2a + b to get 2a - b 2b 4a 0 4a + 4b Reveal answer Fill a bubble to check yourself A Correct answer Explanation To find what must be subtracted, set up the equation: (2a + b) - x = (2a - b). Solving for x gives x = (2a + b) - (2a - b) = 2a + b - 2a + b = 2b.