\(\dfrac{-3}{7}.\dfrac{8}{23}+\dfrac{3}{7}.\dfrac{-15}{23}+2\dfrac{3}{5}\\ =\dfrac{3}{7}.\dfrac{-8}{23}+\dfrac{3}{7}.\dfrac{-15}{23}+\dfrac{13}{5}\\ =\dfrac{3}{7}\left(\dfrac{-8}{23}+\dfrac{-15}{23}\right)+\dfrac{13}{5}\\ =\dfrac{3}{7}.\left(-1\right)+\dfrac{13}{5}\\ =\dfrac{-3}{7}+\dfrac{13}{5}\\ =\dfrac{76}{35}\)
\(=\dfrac{-3}{7}\cdot\dfrac{8}{23}+\dfrac{3}{7}\cdot\dfrac{-15}{23}+\dfrac{13}{5}\\ =\dfrac{3}{7}\cdot\left(\dfrac{-8}{23}+\dfrac{-15}{23}\right)+\dfrac{13}{5}\\ =\dfrac{3}{7}\cdot-1+\dfrac{13}{5}=\dfrac{-3}{7}+\dfrac{13}{5}=\dfrac{76}{35}\)
d) \(\dfrac{-3}{7}\cdot\dfrac{8}{23}+\dfrac{3}{7}\cdot\dfrac{-15}{23}+2\dfrac{3}{5}\)
\(=\dfrac{3}{7}\cdot\dfrac{-8}{23}+\dfrac{3}{7}\cdot\dfrac{-15}{23}+\dfrac{13}{5}\)
\(=\dfrac{3}{7}\cdot\left(\dfrac{-8}{23}+\dfrac{-15}{23}\right)+\dfrac{13}{5}\)
\(=\dfrac{3}{7}\cdot-1+\dfrac{13}{5}\)
\(=-\dfrac{3}{7}+\dfrac{13}{5}=\dfrac{76}{35}\)
help bài 3 câu a ,b, và c help
