a) \(\left(3\sqrt{27}-2\sqrt{75}+\sqrt{363}\right)\sqrt{3}=3\sqrt{81}-2\sqrt{225}+\sqrt{1089}\)
\(=3.9-2.15+33=27-30+33=30\)
b) \(\left(12\sqrt{2}-3\sqrt{18}+2\sqrt{8}\right):\sqrt{2}=12-3\sqrt{9}+2\sqrt{4}\)
\(=12-3.3+2.2=12-9+4=7\)
c) \(\sqrt{7-2\sqrt{10}}+\sqrt{20}+\dfrac{1}{2}\sqrt{8}=\sqrt{\left(\sqrt{5}-\sqrt{2}\right)^2}+2\sqrt{5}+\sqrt{2}\)
\(=\left|\sqrt{5}-\sqrt{2}\right|+2\sqrt{5}+\sqrt{2}=\sqrt{5}-\sqrt{2}+2\sqrt{5}+\sqrt{2}=3\sqrt{5}\)
d) \(\sqrt{3-\sqrt{5}}-\sqrt{3+\sqrt{5}}=\dfrac{\sqrt{2}\sqrt{3-\sqrt{5}}}{\sqrt{2}}-\dfrac{\sqrt{2}\sqrt{3+\sqrt{5}}}{\sqrt{2}}\)
\(=\dfrac{\sqrt{2\left(3-\sqrt{5}\right)}}{\sqrt{2}}-\dfrac{\sqrt{2\left(3+\sqrt{5}\right)}}{\sqrt{2}}=\dfrac{\sqrt{6-2\sqrt{5}}}{\sqrt{2}}-\dfrac{\sqrt{6+2\sqrt{5}}}{\sqrt{2}}\)
\(=\dfrac{\sqrt{\left(\sqrt{5}-1\right)^2}}{\sqrt{2}}-\dfrac{\sqrt{\left(\sqrt{5}+1\right)^2}}{\sqrt{2}}=\dfrac{\left|\sqrt{5}-1\right|}{\sqrt{2}}-\dfrac{\left|\sqrt{5}+1\right|}{\sqrt{2}}\)
\(=\dfrac{\sqrt{5}-1}{\sqrt{2}}-\dfrac{\sqrt{5}+1}{\sqrt{2}}=\dfrac{\sqrt{5}-1-\left(\sqrt{5}+1\right)}{\sqrt{2}}=\dfrac{\sqrt{5}-1-\sqrt{5}-1}{\sqrt{2}}\)
\(=\dfrac{-2}{\sqrt{2}}=\dfrac{-\sqrt{2}.\sqrt{2}}{\sqrt{2}}=\dfrac{-\sqrt{2}}{1}=-\sqrt{2}\)
giải giúp mk câu o vs ạ
