Bài 5 : Tính a) sqrt ((6,4)/(8,1)) b) sqrt ((0,25)/(1,44)) C) sqrt (2(2)/(49))

a) $\sqrt{\frac{6.4}{8.1}} = \frac{\sqrt{6.4}}{\sqrt{8.1}} = \frac{\sqrt{64/10}}{\sqrt{81/10}} = \frac{\frac{8}{\sqrt{10}}}{\frac{9}{\sqrt{10}}} = \frac{8}{9}$<br /><br />b) $\sqrt{\frac{0.25}{1.44}} = \frac{\sqrt{0.25}}{\sqrt{1.44}} = \frac{0.5}{1.2} = \frac{5}{12}$<br /><br />c) $\sqrt{2\frac{2}{49}} = \sqrt{\frac{100}{49}} = \frac{\sqrt{100}}{\sqrt{49}} = \frac{10}{7}$<br />