Bài 1:
a: Ta có: \(2\sqrt{75}-\dfrac{1}{5}\sqrt{125}-\dfrac{1}{4}\sqrt{80}+\sqrt{605}\)
\(=6\sqrt{5}-\sqrt{5}-\sqrt{5}+11\sqrt{5}\)
\(=15\sqrt{5}\)
b: ta có: \(\dfrac{3}{\sqrt{2}-1}+\dfrac{3}{\sqrt{2}+1}-\sqrt{\left(4-3\sqrt{2}\right)^2}\)
\(=3\sqrt{2}+3+3\sqrt{2}-3-3\sqrt{2}+4\)
\(=3\sqrt{2}+4\)