SarkariPYQ

SSC CHSL 2022 PYQ — Question 55

SSC CHSL - 25 May 2022 - Shift 2 • Quantitative Aptitude • Q55

Back to paper

If x + 1x\frac{1}{x} = -13, what is the value of x4 + 1x4\frac{1}{x^4}?

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e. 27887

We know that, (a + b)2 = a2 + b2 + 2ab

Here, a = x and b = 1/x

So, (x + 1/x)2 = x2 + 1/x2 + 2

⇒ x2 + 1/x2 = (-13)2 - 2 = 169 - 2 = 167

Again, (x2 + 1/x2)2 = x4 + 1/x4 + 2

⇒ x4 + 1/x4 = 1672 - 2 = 27889 - 2 = 27887