InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
If a + b+ c = 0, then what is the value of (a + b – c)3 + (c + a – b)3 + (b + c – a)3 ?(a) -8 (a3 + b3 + c3)(b) a3 + b3 + c3(c) 24 abc (d) – 24 abc |
|
Answer» (d) - 24 abc a + b + c = 0 ⇒ a + b = -c, c + a = - b, b + c = – a ∴ (a + b – c)3 + (c + a – b)3 + (b + c – a)3 = (– c – c)3 + (– b – b)3 + (– a– a)3 = (– 2c)3 + (– 2b)3 + (– 2a)3 = – 8c3 – 8b3 – 8a3 = – 8 (a3 + b3 + c3) = – 8 x 3 abc = - 24 abc. |
|