(x + 1) (x - 1) = 0
x + 1 = 0 atau x - 1 = 0
x = -1 atau x = 1
HP = {-1, 1}
2. Melengkapkan Kuadrat Sempurna 4x² + 4x + 1 = 0
4x² + 4x + 1 = 0
x² + ⁴/₄ x + (⁴/₈)² = -¹/₄ + (⁴/₈)²
(x + ¹/₂)² = -¹/₄ + (¹/₂)²
(x + ¹/₂)² = -¹/₄ + ¹/₄
(x + ¹/₂)² = 0
x + ¹/₂ = 0