Final answer:
To complete the square in the equation x² + 3x = 6, add (3/2)² = 9/4 to both sides.
Step-by-step explanation:
To complete the square in the equation x² + 3x = 6, we need to add a certain number to both sides of the equation. The number we need to add is half the coefficient of the x term squared. In this case, the coefficient of the x term is 3, so we need to add (3/2)² = 9/4 to both sides.
Learn more about Completing the square in a quadratic equation