Question

Tính:

B=[-\(\sqrt{2,25}\)+4\(\sqrt{\left(-2,15\right)^2}\)-(3\(\sqrt{\dfrac{7}{6}}\))^2].\(\sqrt{1\dfrac{9}{16}}\)

C=\(3\dfrac{1}{2}\).\(\dfrac{4}{49}\)-[2,(4).\(2\dfrac{5}{11}\)]:(\(\dfrac{-42}{5}\))

Answer 1

Tính:

C = \(3\dfrac{1}{2}.\dfrac{4}{49}-\left[2,\left(4\right).2\dfrac{5}{11}\right]:\left(\dfrac{-42}{5}\right)\)

= \(\dfrac{7}{2}.\dfrac{4}{49}-\left[\left(2+0,\left(1\right).4\right).\dfrac{27}{5}\right].\dfrac{-5}{42}\)

= \(\dfrac{1.2}{1.7}-\left[\left(2+\dfrac{1.4}{9}\right).\dfrac{27}{5}\right].\dfrac{-5}{42}\)

= \(\dfrac{2}{7}-\left[\dfrac{18+4}{9}.\dfrac{27}{5}\right].\dfrac{-5}{42}\)

= \(\dfrac{2}{7}-\left[\dfrac{22.9}{3.5}\right].\dfrac{-5}{42}\)

= \(\dfrac{2}{7}-\dfrac{198}{15}.\dfrac{-5}{42}=\dfrac{2}{7}-\dfrac{11}{3}.\dfrac{-1}{7}\)

= \(\dfrac{2}{7}+\dfrac{11}{21}\) = \(\dfrac{6+11}{21}\) = \(\dfrac{17}{21}\)

Answer 2

\(B=\left[-1.5+4\cdot2.15-9\cdot\dfrac{7}{6}\right]\cdot\dfrac{5}{4}\)

\(=-\dfrac{17}{5}\cdot\dfrac{5}{4}=-\dfrac{17}{4}\)