| Let | f(x) = 2x³ - 3x² -23x +12 | |
| f(4) = 2(4)³ - 3(4)² - 23(4) +12 | ||
| f(4) = 128 - 48 - 92 + 12 | ||
| f(4) = 0 | ||
| The remainder when f(x) is divided by x - 4 is 0 | ||
| ∴ x-4 is a factor of f(x) | ||
| f(3) = 2(3)³ -3(3)² -23(3) +12 | ||
| f(3) = 54 - 27 -69 +12 | ||
| f(3) = -30 | ||
| The remainder when f(x) is divided by x - 3 is -30 |