a/ 5*\(\sqrt{0,01}-\sqrt{0,25}\)
= 5*\(\dfrac{1}{10}-\dfrac{1}{2}\)
= \(\dfrac{1}{2}-\dfrac{1}{2}\)
= 0
b/\(15\dfrac{1}{4}\): (-\(\dfrac{5}{7}\))- 25\(\dfrac{1}{4}\):(-\(\dfrac{5}{7}\))
= 15\(\dfrac{1}{4}\)* (\(\dfrac{-7}{5}\)) - 25\(\dfrac{1}{4}\)*(\(\dfrac{-7}{5}\))
= (\(\dfrac{-7}{5}\))* (15\(\dfrac{1}{4}\) - 25\(\dfrac{1}{4}\))
= (\(\dfrac{-7}{5}\))* (-10)
= 14
Chúc bạn học tốt !!