a)\(\left(\dfrac{-4}{5}\right)^{15}:\left(\dfrac{-4}{5}\right)^{13}=\left(\dfrac{-4}{5}\right)^2=\left(\dfrac{-4}{5}\right)\left(\dfrac{-4}{5}\right)=\dfrac{16}{25}\)
b)\(\dfrac{15}{60}+\dfrac{12}{19}+\dfrac{2}{9}-\dfrac{10}{8}+\dfrac{7}{19}\)
=\(\left(\dfrac{15}{60}-\dfrac{10}{8}\right)+\left(\dfrac{12}{19}+\dfrac{7}{19}\right)+\dfrac{2}{9}\)
\(=\left(\dfrac{1}{4}-\dfrac{5}{4}\right)+\left(\dfrac{12}{19}+\dfrac{7}{19}\right)+\dfrac{2}{9}\)
\(=\left(-1\right)+1+\dfrac{2}{9}\)
\(=0+\dfrac{2}{9}=\dfrac{2}{9}\)
a.
(\(\dfrac{-4}{5}\))15 - 13
= (\(\dfrac{-4}{5}\))2
= \(\dfrac{16}{25}\)
