[tex]\dfrac{\sqrt x-2}{\sqrt x-4}=\dfrac{\sqrt x-6}{\sqrt x-7}\Rightarrow (\sqrt x-2)(\sqrt x-7)=(\sqrt x-4)(\sqrt x-6)
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\it \Rightarrow x-7\sqrt x -2\sqrt x+14 = x -6\sqrt x-4\sqrt x +24\Rightarrow \sqrt x = 10 \Rightarrow x = 100
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.[/tex]