Mathematics for IGCSE & O level - Equations (Section 7 - No. 11)
Which of these equations represents a difference of squares?
x² + 9 = 0
x² + 6x + 9 = 0
x² - 9 = 0
x² - 6x + 9 = 0
คำอธิบาย
This type of equation follows a²-b² pattern and can be factored as (x - 3)(x + 3).