Tính :
a) \(\sqrt {\dfrac{{49}}{{16}}} \); b) \(\sqrt {3\dfrac{1}{{16}}} \);
c) \(\sqrt {2\dfrac{{14}}{{25}}} \); d) \(\sqrt {\dfrac{{2,5}}{{3,6}}} \).
Sử dụng công thức: \(\sqrt {\dfrac{A}{B}} = \dfrac{{\sqrt A }}{{\sqrt B }}.\)
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a) \(\sqrt {\dfrac{{49}}{{16}}} = \dfrac{{\sqrt {49} }}{{\sqrt {16} }} = \dfrac{7}{4} \)
b) \(\sqrt {3\dfrac{{1}}{{16}}} = \sqrt {\dfrac{{49}}{{16}}} = \dfrac{{\sqrt {49} }}{{\sqrt {16} }} = \dfrac{7}{4} \)
c) \(\sqrt {2\dfrac{{14}}{{25}}} = \sqrt {\dfrac{{64}}{{25}}} = \dfrac{{\sqrt {64} }}{{\sqrt {25} }} = \dfrac{8}{5} \)
d) \(\sqrt {\dfrac{{2,5}}{{3,6}}} = \sqrt {\dfrac{{25}}{{36}}} = \dfrac{{\sqrt {25} }}{{\sqrt {36} }} = \dfrac{5}{6}.\)