Bài 28:
a. \(\sqrt{\dfrac{289}{225}}=\dfrac{\sqrt{289}}{\sqrt{225}}=\dfrac{17}{15}\)
b. \(\sqrt{2\dfrac{14}{25}}=\sqrt{\dfrac{64}{25}}=\dfrac{\sqrt{64}}{\sqrt{25}}=\dfrac{8}{5}\)
c. \(\sqrt{\dfrac{0,25}{9}}=\dfrac{\sqrt{0,25}}{\sqrt{9}}=\dfrac{0,5}{3}=\dfrac{1}{6}\)
d. \(\sqrt{\dfrac{8,1}{1,6}}=\dfrac{\sqrt{8,1}}{\sqrt{1,6}}=\dfrac{\dfrac{9\sqrt{10}}{10}}{\dfrac{2\sqrt{10}}{5}}=\dfrac{9}{4}\)
Bài 29:
a. \(\dfrac{\sqrt{2}}{\sqrt{18}}=\dfrac{\left(\sqrt{2}\right)^2}{\sqrt{18}.\sqrt{2}}=\dfrac{2}{6}=\dfrac{1}{3}\)
b. \(\dfrac{\sqrt{15}}{\sqrt{735}}=\dfrac{\left(\sqrt{15}\right)^2}{\sqrt{735}.\sqrt{15}}=\dfrac{15}{105}=\dfrac{1}{7}\)
Câu còn lại tương tự.
