Question

Tính :

a) (\(\sqrt{12}+\sqrt{75}+\sqrt{27}\)) / \(\sqrt{15}\)

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

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

Answer 1

a)\(\left(\sqrt{12}+\sqrt{75}+\sqrt{27}\right):\sqrt{15}\)

\(=\left(2\sqrt{3}+5\sqrt{3}+3\sqrt{3}\right):\sqrt{15}\)

\(=10\sqrt{3}:\sqrt{15}=\sqrt{300}:\sqrt{15}=\sqrt{20}=2\sqrt{5}\)

b) \(\frac{12\sqrt{50}-8\sqrt{200}+7\sqrt{450}}{\sqrt{10}}\)

\(=\frac{60\sqrt{2}-80\sqrt{2}+105\sqrt{2}}{\sqrt{10}}\)

\(=\frac{85\sqrt{2}}{10}=\frac{17\sqrt{2}}{2}\)

c)\(\frac{\sqrt{\frac{1}{7}}-\sqrt{\frac{16}{7}}+\sqrt{\frac{9}{7}}}{7}=\frac{\frac{1}{\sqrt{7}}-\frac{4}{\sqrt{7}}+\frac{3}{\sqrt{7}}}{7}=\frac{0}{7}=0\)