แบบฝึกหัด 2.1
จะแยกตัวประกอบของพหุนามต่อไปนี้
6 729 +(X-2) ³
95m 729 + (x-2)³ = 9³ + (x-2) ³
3
- [9 + (x-2)] [9²-9(x-2) + (x-2)²]
2
= (9+x-2) [81- (9x-18) + (x²- 2x (2) +2²)]
= (x + 7) [(81-9x + 18) + (x² - 4x +4)]
2
= (X+7) (81-9x + 18+ X² - 4x +4)
= (x+7) (x²-13x+103)
14 (4x+3)³-125
☆
ado
3
35m (4x+3)³-125 = (4x+3) ³ - 5³
2
= [(4x +3)-5][(4x +3)² + (4x+3)(5) +5°
(4x+3-5) (___(2)(4x) (3) +3²)