Mathematics for IGCSE & O level - Algebraic Manipulation (Section 3 - No. 15)
Which is the complete square form for x² + 2x - 3?
(x + 1)² - 4
(x - 1)² - 4
(x + 1)² + 4
(x - 1)² + 4
解释
To complete the square: (b/2)² = (2/2)² = 1, adding and subtracting 1 gives: x² + 2x + 1 - 1 - 3, giving us (x + 1)² - 4