i: =28/5x1/(-7)=28/-35=-4/5
j: \(=\left(4+\dfrac{5}{9}\right)\cdot\dfrac{-7}{5}+\left(5+\dfrac{4}{9}\right)\cdot\dfrac{-7}{5}\)
\(=\dfrac{-7}{5}\cdot10=-14\)
l: \(=\dfrac{-2}{3}\cdot4+\dfrac{-2}{3}\cdot\dfrac{4}{3}\)
\(=\dfrac{-8}{3}+\dfrac{-8}{9}=\dfrac{-24-8}{9}=-\dfrac{32}{9}\)
l)
\(=\left(-\dfrac{2}{3}\right)\times4+\left(-\dfrac{2}{3}\right)\times\dfrac{4}{3}\)
\(=\left(-\dfrac{2}{3}\right)\times\left(4+\dfrac{4}{3}\right)=-\dfrac{2}{3}\times\dfrac{16}{3}=\dfrac{-32}{9}\)
i) \(\dfrac{28}{5}:\left(-7\right)\\ =\dfrac{28}{5}.-\dfrac{1}{7}\\ =-\dfrac{4}{5}\)
k. \(4\dfrac{5}{9}:\left(-\dfrac{5}{7}\right)+5\dfrac{4}{9}:\left(-\dfrac{5}{7}\right)\\ =\left(4\dfrac{5}{9}+5\dfrac{4}{9}\right):\left(-\dfrac{5}{7}\right)\\ =\left(\dfrac{41}{9}+\dfrac{49}{9}\right):\left(-\dfrac{5}{7}\right)\\ =10:\left(-\dfrac{5}{7}\right)\\ =10.-\dfrac{7}{5}\\ =-14\)
l. \(\left(-\dfrac{2}{3}\right):\dfrac{1}{4}+\left(-\dfrac{2}{3}\right):\dfrac{3}{4}\\ =\left(-\dfrac{2}{3}\right):\left(\dfrac{1}{4}+\dfrac{3}{4}\right)\\ =-\dfrac{2}{3}:1\\ =-\dfrac{2}{3}\)
