Tentukan akar-akar suku banyak X3 +2x2 -5x-6=0

jawab

x³ + 2x² - 5x - 6 =0

dengan horner
.....1.....2....-5....-6
(2).......2.....8.....6
.....1....4.....3,,,[ 0 ]
maka

x³ + 2x² - 5x - 6 = 
= (x -2)(x² + 4x + 3)
= (x - 2)(x + 1)(x + 3)
x = 2
x = -1
x = - 3