The problem chosen in this 17th video on SSC CGL level Algebra in a few steps could be solved lightning quick all in mind by converting target expression in terms of a square of sum of inverses and then evaluating the sum of inverses using awkward looking surd variable by using the basic algebraic concepts of addition of square of sums. The deductions are explained in details. The concepts and techniques are valuable as these help to solve a large variety of algebra problems in just a few steps. The video should be useful for SSC CGL Tier II, CAT or GMAT as well.
Detailed alternate solution are available in the article at How to solve difficult SSC CGL level surd algebra question by repeated componendo dividendo 17.