A. 1, -2, 3 B. 1, 2, -3, C. -1, -2, 3 D. -1, 2, -3
Correct Answer: A
Explanation
Equation: x\(^3\) - 2x\(^2\) - 5x + 6 = 0. First, bring out a\(_n\) which is the coefficient of x\(^3\) = 1. Then, a\(_0\) which is the coefficient void of x = 6. The factors of a\(_n\) = 1; The factors of a\(_0\) = 1, 2, 3 and 6. The numbers to test for the roots are \(\pm (\frac{a_0}{a_n})\). = \(\pm (1, 2, 3, 6)\). Test for +1: 1\(^3\) - 2(1\(^2\)) - 5(1) + 6 = 1 - 2 - 5 + 6 = 0. Therefore x = 1 is a root of the equation. Using long division method, \(\frac{x^3 - 2x^2 - 5x + 6}{x - 1}\) = x\(^2\) - x - 6. x\(^2\) - x - 6 = (x - 3)(x + 2). x = -2, 3. \(\therefore\) The roots of the equation = 1, -2 and 3.