Question

c, \(\dfrac{-3}{8}\).\(\dfrac{2}{5}\)+\(\dfrac{-3}{8}\).\(\dfrac{14}{5}\)                     d, (\(\dfrac{1}{4}\)+\(\dfrac{11}{9}\)):\(\dfrac{34}{5}\)+(\(\dfrac{-2}{9}\)+\(\dfrac{29}{4}\)):\(\dfrac{34}{5}\)

Answer 1

\(c,\dfrac{-3}{8}.\dfrac{2}{5}+\dfrac{-3}{8}.\dfrac{14}{5}\\ =\dfrac{-3}{8}.\left(\dfrac{2}{5}+\dfrac{14}{5}\right)\\ =\dfrac{-3}{8}.\dfrac{16}{5}\\ =\dfrac{-6}{5}\\ d,\left(\dfrac{1}{4}+\dfrac{11}{9}\right):\dfrac{34}{5}+\left(\dfrac{-2}{9}+\dfrac{29}{4}\right):\dfrac{34}{5}\\ =\left(\dfrac{1}{4}+\dfrac{11}{9}\right).\dfrac{5}{34}+\left(\dfrac{-2}{9}+\dfrac{29}{4}\right).\dfrac{5}{34}\\ =\left(\dfrac{1}{4}+\dfrac{11}{9}+\dfrac{-2}{9}+\dfrac{29}{4}\right).\dfrac{5}{34}\\ =\left[\left(\dfrac{1}{4}+\dfrac{29}{4}\right)+\left(\dfrac{11}{9}+\dfrac{-2}{9}\right)\right].\dfrac{5}{34}\\ =\left(\dfrac{15}{2}+1\right).\dfrac{5}{34}\\ =\dfrac{17}{2}.\dfrac{5}{34}\\ =\dfrac{5}{4}\)

Answer 2

c) \(\dfrac{-3}{8}.\dfrac{2}{5}+\dfrac{-3}{8}.\dfrac{14}{5}\)

\(=\dfrac{-3}{8}.\left(\dfrac{2}{5}+\dfrac{14}{5}\right)\)

\(=\dfrac{-3}{8}.\dfrac{16}{5}\)

\(=\dfrac{-6}{5}\)

Giải thích rút gọn 16 cho 8 được 2