SSC CGL 2021 PYQ — Question 66

The correct answer is option 4 i.e. 58.

On solving the LHS part first we get,

= (56$\sqrt{7}$x³ - 2$\sqrt{2}$y³) $\div$ (2$\sqrt{7}$x-$\sqrt{2}$y)

= (2$\sqrt{7}$x)³ - ($\sqrt{2}$y)³  $\div$ (2$\sqrt{7}$x-$\sqrt{2}$y)

= ( 2$\sqrt{7}$x-$\sqrt{2}$y)(28x² + 2y² + 2$\sqrt{14}$xy) $\div$ (2$\sqrt{7}$x-$\sqrt{2}$y)

28x² + 2y² + 2$\sqrt{14}$xy = Ax² + By² - Cxy

On comparing both sides we get,

A = 28, B = 2 and C = -2$\sqrt{14}$

 A + B - $\sqrt{14}$C = 28 + 2 + 28 = 58.