Question

1. tính giá trị của các biểu thức sau

a. \(15\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)-25\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)\)

b. \(\sqrt{0,16}-\sqrt{0,25}\)

Answer 1

a, \(15\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)-25\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)\)

\(=15\dfrac{1}{4}.\left(-\dfrac{7}{5}\right)-25\dfrac{1}{4}.\left(-\dfrac{7}{5}\right)\)

\(=-\dfrac{7}{5}.\left(15\dfrac{1}{4}-25\dfrac{1}{4}\right)\)

\(=-\dfrac{7}{5}.\left(-10\right)\)

\(=\dfrac{7}{5}.10\)

\(=\dfrac{7}{1}.2\)

\(=14\)

b, \(\sqrt{0.16}-\sqrt{0.25}\)

\(=0.4-0.5\)

\(=-0.1\)