Question
$\frac{1}{\sqrt9-\sqrt8}$ is equal to:

Answer

  1. $3+2\sqrt2$
    Solution:
    $\frac{1}{\sqrt9-\sqrt8}$
    $=\frac{1}{\sqrt9-\sqrt8}\times\frac{{\sqrt9+\sqrt8}}{{\sqrt9+\sqrt8}}$
    $\frac{{\sqrt9+\sqrt8}}{\big(\sqrt9\big)^2-\big(\sqrt8\big)^2}$
    $=\frac{{\sqrt9+\sqrt8}}{9-8}$
    $={\sqrt9+\sqrt8}$
    $=3+2\sqrt2$
    Hence, correct option is (a).

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