Question

B1: Tính:

a, \(\sqrt{72}\div\sqrt{8}\)

b, \((\sqrt{28}-\sqrt{7}+\sqrt{112})\div\sqrt{7}\)

B2: Tính:

a, \(\sqrt{\dfrac{49}{8}}\div\sqrt{3\dfrac{1}{8}}\)

b, \(\sqrt{54x}\div\sqrt{6x}\)

c, \(\sqrt{\dfrac{1}{125}}\times\sqrt{\dfrac{32}{35}}\div\sqrt{\dfrac{56}{225}}\)

giúp em với ạ , em cảm mơn 

Answer 1

Bài 1: 

a) \(\sqrt{72}:\sqrt{8}=\sqrt{72:8}=3\)

b) \(\left(\sqrt{28}-\sqrt{7}+\sqrt{112}\right):\sqrt{7}=5\sqrt{7}:\sqrt{7}=5\)

Bài 2: 

a) \(\sqrt{\dfrac{49}{8}}:\sqrt{3\dfrac{1}{8}}=\sqrt{\dfrac{49}{8}:\dfrac{25}{8}}=\sqrt{\dfrac{49}{25}}=\dfrac{7}{5}\)

b) \(\sqrt{54x}:\sqrt{6x}=\sqrt{54x:6x}=\sqrt{9}=3\)

c) \(\sqrt{\dfrac{1}{125}}\cdot\sqrt{\dfrac{32}{35}}:\sqrt{\dfrac{56}{225}}\)

\(=\dfrac{\sqrt{5}}{25}\cdot\dfrac{4\sqrt{2}}{\sqrt{35}}:\dfrac{2\sqrt{14}}{15}\)

\(=\dfrac{\sqrt{5}\cdot4\sqrt{2}\cdot15}{25\cdot\sqrt{35}\cdot\sqrt{14}\cdot2}\)

\(=\dfrac{6}{35}\)