If √x + = 3, then the value of x3 + 1/x3 is:
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Correct answer: B
Explanation
The correct answer is option 2 i.e. 322.
√x + = 3.
On squaring both sides we get,
x + 1/x + 2 = 9
x + 1/x = 7
On cubing both side we get,
x3 + 1/x3 + 3(x + 1/x) = 343
x3 + 1/x3 = 343 - 21
x3 + 1/x3 = 322.