c: \(\left(-\dfrac{2}{3}\right)^3-\dfrac{1}{9}\cdot\dfrac{12}{-18}-4\cdot\dfrac{-3}{24}\)
\(=-\dfrac{8}{27}+\dfrac{1}{9}\cdot\dfrac{2}{3}+4\cdot\dfrac{3}{24}\)
\(=-\dfrac{8}{27}+\dfrac{2}{27}+4\cdot\dfrac{1}{8}\)
\(=-\dfrac{6}{27}+\dfrac{1}{2}=\dfrac{-2}{9}+\dfrac{1}{2}=\dfrac{-4+9}{18}=\dfrac{5}{18}\)
d: \(\left(-\dfrac{4}{5}\right)^2-\dfrac{-19}{45}\cdot\dfrac{-18}{38}-\left(-\dfrac{2}{3}\right)^2\)
\(=\dfrac{16}{25}-\dfrac{19}{45}\cdot\dfrac{18}{38}-\dfrac{4}{9}\)
\(=\dfrac{16}{25}-\dfrac{4}{9}-\dfrac{19}{38}\cdot\dfrac{18}{45}\)
\(=\dfrac{144-100}{225}-\dfrac{1}{2}\cdot\dfrac{2}{5}\)
\(=\dfrac{44}{225}-\dfrac{1}{5}=\dfrac{44-45}{225}=-\dfrac{1}{225}\)
e: \(\dfrac{-1}{4}\cdot\dfrac{-2}{5}-3\cdot\left(-\dfrac{2}{5}\right)^2-\left(-\dfrac{1}{3}\right)^3\)
\(=\dfrac{1}{2\cdot5}-3\cdot\dfrac{4}{25}+\dfrac{1}{27}\)
\(=\dfrac{1}{10}-\dfrac{12}{25}+\dfrac{1}{27}=\dfrac{-463}{1350}\)
g: \(\dfrac{2}{-4^2}-\dfrac{14}{19}\cdot\dfrac{-38}{7}-3\cdot\left(-\dfrac{2}{5}\right)^2\)
\(=\dfrac{-2}{16}+\dfrac{14}{7}\cdot\dfrac{38}{19}-3\cdot\dfrac{4}{25}\)
\(=-\dfrac{1}{8}+4-\dfrac{12}{25}=\dfrac{679}{200}\)
h: \(\dfrac{-3}{4}\cdot\dfrac{-8}{27}-\left(-\dfrac{1}{2}\right)\cdot\left(-\dfrac{4}{5}\right)-\left(-2\right)^3\)
\(=\dfrac{3}{27}\cdot\dfrac{8}{4}-\dfrac{1}{2}\cdot\dfrac{4}{5}+8\)
\(=\dfrac{2}{9}-\dfrac{2}{5}+8=\dfrac{352}{45}\)
giúp bài 6 này vs ạ. thanks
