Exams › SSC CGL (Prelims) › General

If \(x + \frac{3}{x} = 8\), find the value of \(x^3 + \frac{27}{x^3}\).

1. 440
2. 512
3. 398
4. 480

Correct answer: 440

Solution

Using \((x+\frac{3}{x})^3 = x^3 + \frac{27}{x^3} + 3\cdot x\cdot \frac{3}{x}\left(x+\frac{3}{x}\right)\), we can isolate the required expression. Substituting the given value gives 440.

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