Question

Tính:

a) \(\sqrt{7}.\sqrt{55}.\sqrt{35}.\sqrt{11}\)

b) \(\frac{\sqrt{144}}{23}:\frac{\sqrt{16}}{23}\)

c) \(\frac{\sqrt{5}}{\sqrt{125}}\)

d) \(\frac{\sqrt{135}}{\sqrt{15}}\)

Answer 1

a) \(\sqrt{7}.\sqrt{55}.\sqrt{35}.\sqrt{11}=\sqrt{7.55.35.11}=\sqrt{7.5.11.5.7.11}=\sqrt{\left(5.7.11\right)^2}\)

\(=5.7.11=385\)

b) \(\frac{\sqrt{144}}{23}:\frac{\sqrt{16}}{23}=\frac{\sqrt{144}}{23}.\frac{23}{\sqrt{16}}=\frac{\sqrt{144}}{\sqrt{16}}=\sqrt{\frac{144}{16}}=\sqrt{9}=3\)

c) \(\frac{\sqrt{5}}{\sqrt{125}}=\sqrt{\frac{5}{125}}=\sqrt{\frac{1}{25}}=\frac{1}{5}\)

d) \(\frac{\sqrt{135}}{\sqrt{15}}=\sqrt{\frac{135}{15}}=\sqrt{9}=3\)

Answer 2

a)\(\sqrt{7}.\sqrt{55}.\sqrt{35}.\sqrt{11}=\left(\sqrt{7}.\sqrt{355}\right).\left(\sqrt{35}.\sqrt{11}\right)=\sqrt{385}.\sqrt{385}=385\)

b) \(\frac{\sqrt{144}}{23}:\frac{\sqrt{16}}{23}=\frac{12}{23}.\frac{23}{4}=3\)

c) \(\frac{\sqrt{5}}{\sqrt{125}}=\sqrt{\frac{5}{125}}=\sqrt{\frac{1}{25}}=\frac{1}{\sqrt{5}}=\frac{\sqrt{5}}{5}\)

d) \(\frac{\sqrt{135}}{\sqrt{15}}=\sqrt{\frac{135}{15}}=\sqrt{9}=3\)

Answer 3

           Bài làm :

\(\text{a)}\sqrt{7}.\sqrt{55}.\sqrt{35}.\sqrt{11}=\left(\sqrt{7}.\sqrt{355}\right).\left(\sqrt{35}.\sqrt{11}\right)=\sqrt{385}.\sqrt{385}=385\)

 \(\text{b)}\frac{\sqrt{144}}{23}\div\frac{\sqrt{16}}{23}=\frac{12}{23}.\frac{23}{4}=\frac{12}{4}=3\)

 \(\text{c)}\frac{\sqrt{5}}{\sqrt{125}}=\sqrt{\frac{5}{125}}=\sqrt{\frac{1}{25}}=\frac{1}{5}\)

 \(\text{d)}\frac{\sqrt{135}}{\sqrt{15}}=\sqrt{\frac{135}{15}}=\sqrt{9}=3\)