If a + b + c = 1, ab + bc + ca = -22 and abc = -40, then what is the value of (a3 + b3 +c3) + 5?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. -48.
a3 + b3 + c3 = (a + b + c)3 - 3(a + b + c)(ab + bc + ca) + 3abc
⇒ a3 + b3 + c3 = (1)3 - 3 × 1 × -22 + 3 × -40
⇒ a3 + b3 + c3 = 1 + 66 - 120
⇒ a3 + b3 + c3 = -53
Value of (a3 + b3 +c3) + 5 = -53 + 5 = -48