a/ $\sqrt{(1-\sqrt 2)^2}\\=|1-\sqrt 2|\\=\sqrt 2-1(vì\,\,1-\sqrt 2<0)$
Vậy $\sqrt{(1-\sqrt 2)^2}=\sqrt 2-1$
b/ $\dfrac{\sqrt{2300}}{\sqrt{23}}\\=\dfrac{\sqrt{23.100}}{\sqrt{23}}\\=\dfrac{\sqrt{23}.\sqrt{100}}{\sqrt{23}}\\=\sqrt{100}\\=10$
Vậy $\dfrac{\sqrt{2300}}{\sqrt{23}}=10$
c/ $\sqrt{10}.\sqrt{40}\\=\sqrt{400}\\=20$
Vậy $\sqrt{10}.\sqrt{40}=20$
d/ $\sqrt[3]{-125}\\=\sqrt[3]{(-5)^3}\\=-5$
Vậy $\sqrt[3]{-125}=-5$
