Question

1]

a) \(\left(12\sqrt{50}-8\sqrt{200}+7\sqrt{450}\right):\sqrt{10}\)

b) \(\left(\frac{\sqrt{1}}{7}-\sqrt{\frac{16}{7}}+\sqrt{\frac{9}{7}}\right):\sqrt{7}\)

Answer 1

Bài 1:

a) Ta có: \(\frac{12\sqrt{50}-8\sqrt{200}+7\sqrt{450}}{\sqrt{10}}\)

\(=\frac{12\cdot\sqrt{5}\cdot\sqrt{10}-8\cdot\sqrt{20}\cdot\sqrt{10}+7\cdot\sqrt{45}\cdot\sqrt{10}}{\sqrt{10}}\)

\(=\frac{\sqrt{10}\left(12\sqrt{5}-8\sqrt{20}+7\sqrt{45}\right)}{\sqrt{10}}\)

\(=12\sqrt{5}-8\sqrt{20}+7\sqrt{45}\)

\(=\sqrt{5}\left(12-16+21\right)\)

\(=17\sqrt{5}\)

b) Ta có: \(\frac{\frac{\sqrt{1}}{7}-\sqrt{\frac{16}{7}}+\sqrt{\frac{9}{7}}}{\sqrt{7}}\)

\(=\left(\frac{1}{\sqrt{7}}-\frac{4}{\sqrt{7}}+\frac{3}{\sqrt{7}}\right)\cdot\frac{1}{\sqrt{7}}\)

\(=0\cdot\frac{1}{\sqrt{7}}=0\)