Mathematics for IGCSE & O level - Algebraic Manipulation (Section 3 - No. 22)
What is the result of completing the square on the expression x² + 12x + 30?
(x + 6)² - 6
(x + 6)² + 30
(x - 6)² + 30
(x - 6)² - 6
解释
Add and subtract (12/2)² which is 36. x² + 12x + 36 - 36 + 30 = (x + 6)² - 6