Problem: if | x - 20 | = 40 what is the sum of all the values of x .
Rationale: "there will be two cases x - 20 = 40 and x - 20 = - 40 solve for x = > x = 40 + 20 = > x = 60 or x = - 40 + 20 = > x = - 20 the sum of both values will be 60 + - 20 = 40 answer is d"
annotated_formula: subtract(add(40, 20), subtract(40, 20))