SSC CHSL 2022 PYQ — Question 74

SSC CHSL - 31 May 2022 - Shift 3 • Quantitative Aptitude • Q74

If ab+ba\frac{a}{b}+\frac{b}{a} = -1, a ≠ 0, b ≠ 0, then the value of 6(a3 - b3) is:

Show answer & explanation

Correct answer: C

Explanation

The correct answer is option 3 i.e. 0

Given:

ab+ba\frac{a}{b}+\frac{b}{a} = -1

Formula Used:

a3 - b3 = (a - b)(a2 + b2 + ab)

Explanation:

According to the given question,

ab+ba\frac{a}{b}+\frac{b}{a} = -1 = a2 + b2 = -ab ⇒ a2 + b2 + ab = 0

Now, 6(a3 - b3 ) = 6(a - b)(a2 + b2 + ab) = 6(a - b) × 0 = 0

Hence the required answer is 0.