.If x, y, z are the three factors of a³ – 7a – 6, then value of (x + y + z) will be
3a
3
6
a
Correct Option: A
a³ – 7a – 6 = 0 When a = –1 f(a) = –1 + 7 – 6 = 0 ∴ (a + 1) is a factor. ∴ a² – a – 6 = a² – 3a + 2a – 6 = a (a – 3) + 2 (a – 3) = (a – 3) (a + 2) ∴ x + y + z = a + 1 + a – 3 + a + 2 = 3a
