Question 88

If $$2\sqrt{2}x^3-3\sqrt{3}y^3=\left(\sqrt{2}x-\sqrt{3}y\right)\left(Ax^2+By^2+Cxy\right)$$, then the value of $$A^2 + B^2 - C^2$$ is:

Solution

$$2\sqrt{2}x^3-3\sqrt{3}y^3=\left(\sqrt{2}x-\sqrt{3}y\right)\left(Ax^2+By^2+Cxy\right)$$
($$\because$$ $$a^3 - b^3 = (a - b)(a^2 + ab + b^2)$$)
On compression,
A = $$(\sqrt{2})^2$$ = 2
A = $$(-\sqrt{3})^2$$ = 3
C = $$\sqrt{2}\sqrt{3} = \sqrt{6}$$
Now,
$$A^2 + B^2 - C^2$$
= $$2^2 + 3^2 - (\sqrt{6})^2$$
= 4 + 9 - 6
= 7


Create a FREE account and get:

  • Free SSC Study Material - 18000 Questions
  • 230+ SSC previous papers with solutions PDF
  • 100+ SSC Online Tests for Free

cracku

Boost your Prep!

Download App