SSC Selection Post 2022 PYQ — Question 58

The correct answer is option 4 i.e. 2x(x² + $3\over{y^2}$).

(a - b)³ + (a + b)³ = 2a³ + 6ab²

⇒ $(x - \frac{1}{y})^3 + (x + \frac{1}{y})^3$ 

⇒ $2x^3 + 6x \times \left(\frac{1}{y}\right)^2$

⇒ $2x^3 + \frac{6x}{y^2}$ = 2x(x² + $3\over{y^2}$)