Amira is solving the equation x2 – 6x = 1. Which value must be added to both sides of the equation to make the left side a perfect-square trinomial?

To complete the square for x² – 6x, take half of the coefficient of x (–6 ÷ 2 = –3) and square it: (–3)² = 9. Adding 9 to both sides makes the left side x² – 6x + 9 = (x – 3)², a perfect-square trinomial. The value is 9, choice C.

AI-written and checked against the verified answer.