Question

solution of this question

Answer 1

the answer of given is √37

Answer 2

${x}^{2} + \frac{9}{ {x}^{2} } = 31 \\ {x}^{2} + \frac{9}{ {x}^{2} } + 6 - 6 = 31 \\ {x}^{2} + \frac{9}{ {x}^{2} } + 2 \times \frac{3x}{x} - 6 = 31 \\ (x + \frac{3}{x} ) ^{2} = 31 + 6$
$(x + \frac{3}{x} ) = \sqrt{37}$
hope it helps