If a2 + b2 = 99 and ab = 11, (a > 0, b > 0) then the value of (a3 + b3) is:
Show answer & explanation
Correct answer: B
Explanation
Correct Answer is option 2 i.e. 968
|
Concept |
Understanding |
Application |
|
(a + b)2 = a2 + b2 + 2ab a3 + b3 = (a + b) (a2 + b2 – ab) |
Given: a2 + b2 = 99 and ab = 11 |
(a + b)2 = a2 + b2 + 2ab (a + b)2 = 99 + 22 = 121 (a + b) = 11 Now, a3 + b3 = (a + b) (a2 + b2 – ab) = 11 × (99 – 11) = 11 × 88 = 968 |