Question

If $x=\sqrt{6}+\sqrt{5}$, then $x^2+\frac{1}{x^2}-2=$

(a) $2\sqrt{6}$

(b) $2\sqrt{5}$

(c) 24

(d) 20

Answer 1

Given that.Hence is given as

We need to find

We know that rationalization factor for is. We will multiply numerator and denominator of the given expression by, to get

We know that therefore,

Hence the value of the given expression is 20 and correct option is (d).