✔ 最佳答案
3x² + 2x - 1 = 0
x² + 1/3x = 1/3 + (1/3)²
x² + 1/3x = 3/9 + 1/9
(x + 1/3)² = 4/9
x + 1/3 = ± 2/3
= x + 1/3 - 2/3, = x - 1/3, = 3x - 1
= x + 1/3 + 2/3, = x + 3/3, = x + 1
Answer: (3x - 1)(x + 1)
Proof:
= (3x - 1)(x + 1)
= 3x(x) + 3x(1) - 1(x) - 1(1)
= 3x² + 3x - x - 1
= 3x² + 2x - 1