Question

Tính

a, \(\sqrt{45}\) : \(\sqrt{80}\)

b, \(\sqrt{\frac{3}{15}}\) : \(\sqrt{\frac{36}{45}}\)

c, (\(7\sqrt{48}\) + \(3\sqrt{27}\) - \(2\sqrt{12}\)) : \(\sqrt{3}\)

d, \(\sqrt{\frac{125}{245}}\)

e, \(\sqrt{\frac{84^2-37^2}{47}}\)

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Answer 1

a)\(\sqrt{45}:\sqrt{80}\)

= \(\sqrt{45:80}\)

=\(\sqrt{9:16}\)

= \(\sqrt{9}:\sqrt{16}\)

= \(\frac{3}{4}\)

b)\(\sqrt{\frac{3}{15}}:\sqrt{\frac{36}{45}}\)

= \(\sqrt{\frac{1}{5}}:\sqrt{\frac{4}{5}}\)

= \(\sqrt{\frac{1}{5}.\frac{5}{4}}\)

= \(\sqrt{\frac{1}{4}}\)

=\(\frac{1}{2}\)

c)\(\left(7\sqrt{48}+3\sqrt{27}-2\sqrt{12}\right):\sqrt{3}\)

= \(\left(7\sqrt{4^2.3}+3\sqrt{3^2.3}-2\sqrt{2^2.3}\right):\sqrt{3}\)

=\(\left(28\sqrt{3}+9\sqrt{3}-4\sqrt{3}\right):\sqrt{3}\)

=28+9-4

=33

d) \(\sqrt{\frac{125}{245}}\)

= \(\sqrt{\frac{25}{49}}\)

= \(\frac{\sqrt{25}}{\sqrt{49}}\)

= \(\frac{5}{7}\)