Điều kiện : x > 0
pt <=> \(\left(0,5.\sqrt{2}-\sqrt{\frac{8}{25}} +\sqrt{\frac{1}{4}}\right).\sqrt{\frac{1}{x}}=\frac{1}{5}\)
<=> \(\left(\frac{\sqrt{2}}{2}-\frac{2\sqrt{2}}{5}+\frac{1}{2}\right).\sqrt{\frac{1}{x}}=\frac{1}{5}\)
<=> \(\frac{\sqrt{2}+5}{10}.\sqrt{\frac{1}{x}}=\frac{1}{5}\) <=> \(\sqrt{\frac{1}{x}}=\frac{1}{5}:\frac{\sqrt{2}+5}{10}=\frac{2}{\sqrt{2}+5}\)
=> \(\sqrt{x}=\frac{\sqrt{2}+5}{2}\) => x = \(\frac{\left(\sqrt{2}+5\right)^2}{4}\) (thỏa mãn)
Vậy....