Question

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Answer 1

\(a,=\left[\dfrac{\sqrt{7}\left(\sqrt{2}-1\right)}{1-\sqrt{2}}-\dfrac{\sqrt{5}\left(\sqrt{3}-1\right)}{1-\sqrt{3}}\right]\left(\sqrt{7}+\sqrt{5}\right)\\ =\left(-\sqrt{7}+\sqrt{5}\right)\left(\sqrt{7}+\sqrt{5}\right)=5-7=-2\)