If x = 
and y is the reciprocal of x, then what is the value of (x³ + y³) ?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 ie 488.
x =
y = 1/x = 
We know , x + (1/x) = a
= a
= a
16/2 = a
a = 8
x³ + (1/x³) = a³ - 3a
= 64 × 8 - 3 × 8
= 8 × (64 - 3)
= 8 × 61 = 488