a) \(\dfrac{2}{3}\).x + \(\dfrac{1}{2}\)= \(\dfrac{1}{10}\)
=> \(\dfrac{2}{3}\).x = \(\dfrac{1}{10}\)- \(\dfrac{1}{2}\)= \(\dfrac{-2}{5}\)
=> x= \(\dfrac{-2}{5}\): \(\dfrac{2}{3}\)= \(\dfrac{-2}{5}\). \(\dfrac{3}{2}\)
=> x = \(\dfrac{-3}{5}\)
Vậy x = \(\dfrac{-3}{5}\)
b) \(\dfrac{2}{3}\).x + \(\dfrac{1}{5}\)= \(\dfrac{7}{10}\)
=> \(\dfrac{2}{3}\).x = \(\dfrac{7}{10}\)- \(\dfrac{1}{5}\)= \(\dfrac{1}{2}\)
=> x = \(\dfrac{1}{2}\): \(\dfrac{2}{3}\)= \(\dfrac{1}{2}\). \(\dfrac{3}{2}\)
=> x = \(\dfrac{3}{4}\)
Vậy x = \(\dfrac{3}{4}\)
c) ( \(3\dfrac{4}{5}\)- 2.x) . \(1\dfrac{1}{3}\)= \(5\dfrac{5}{7}\)
=> ( \(\dfrac{19}{5}\) - 2.x) . \(\dfrac{4}{3}\)= \(\dfrac{40}{7}\)
=> ( \(\dfrac{19}{5}\)- 2.x) = \(\dfrac{40}{7}\): \(\dfrac{4}{3}\)= \(\dfrac{40}{7}\). \(\dfrac{3}{4}\)
=> ( \(\dfrac{19}{5}\)- 2.x) = \(\dfrac{30}{7}\)
=> 2.x = \(\dfrac{30}{7}\)- \(\dfrac{19}{5}\)= \(\dfrac{17}{35}\)
=> x = \(\dfrac{17}{35}\) : 2 = \(\dfrac{17}{35}\). \(\dfrac{1}{2}\)
=> x = \(\dfrac{17}{70}\)
Vậy x = \(\dfrac{17}{70}\)
d) \(\dfrac{x}{7}\)= \(\dfrac{6}{-21}\)
=> \(x\)= \(\dfrac{6.7}{-21}\)
=> \(x\)= -2