If $$\sqrt x + \frac{1}{{\sqrt x }} = 3,$$ then the value of $${x^3} + \frac{1}{{{x^3}}}$$ is:
A. 326
B. 322
C. 324
D. 422
Answer: Option B
Solution (By Examveda Team)
$$\eqalign{ & \sqrt x + \frac{1}{{\sqrt x }} = 3 \cr & x + \frac{1}{x} = 7 \cr & {x^3} + \frac{1}{{{x^3}}} = {7^3} - 3 \times 7 \cr & = 343 - 21 \cr & = 322 \cr} $$This Question Belongs to Arithmetic Ability >> Algebra
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