Jawabanmu

2014-06-05T14:12:53+07:00
F(x) = x³ - 6x² + 9x + 1
turun pada saat f '(x) < 0
3x² - 12x + 9 < 0
3(x² - 4x + 3) < 0
3(x - 1)(x - 3) < 0
1 < x < 3