?
If $$\sqrt x + \frac{1}{{\sqrt x }} = 3,$$ then the value of $${x^3} + \frac{1}{{{x^3}}}$$ is:
Answer & Solution
Correct Answer:
Option
B
$$\eqalign{
& \sqrt x + \frac{1}{{\sqrt x }} = 3 \cr
& x + \frac{1}{x} = 7 \cr
& {x^3} + \frac{1}{{{x^3}}} = {7^3} - 3 \times 7 \cr
& = 343 - 21 \cr
& = 322 \cr} $$
Join the Discussion
Login to post a comment or share your explanation.
Login