What number must you add to complete the square?

x2 - 18x = 29

81

Step-by-step explanation:

Given

x² - 18x = 29

To complete the square

add (half the coefficient of the x - term) ² to both sides

x² + 2 ( - 9) x + ( - 9) ² = 29 + ( - 9) ²

x² + 2 ( - 9) x + 81 = 29 + 81

(x - 9) ² = 110