Question

If a + b = 5, ab = 14/3 then a³ + b³ =?
1. 52
2. 54
3. 56
4. 55

Answer 1

Correct Answer - Option 4 : 55

Given:

a + b = 5, ab = 14/3

Formula used:

a³ + b³ = (a + b)(a² – ab + b²) = (a + b) [(a + b)² – 3ab]

Calculation:

 Putting values we get, a³ + b³ = 5 [25 – 3 × 14/3]

= 5 [25 – 14] = 5 × 11 = 55