2015 · Q16
If a, b and c satisfy the equation x³ - 3x² + 2x + 1 = 0 then what is the value of 1/a + 1/b + 1/c ?
Elementary MathematicsProfit and Loss
- A-1/2
- B2
- C-2
- D1/2
Explanation
For x^3 - 3x^2 + 2x + 1 = 0 with roots a, b, c: ab + bc + ca = 2 and abc = -1. So 1/a + 1/b + 1/c = (ab + bc + ca)/abc = 2/(-1) = -2. Hence option (c).