a: \(\Leftrightarrow\left(x-\dfrac{2}{3}\right)\cdot\dfrac{5}{6}=\dfrac{-4}{15}+\dfrac{2}{5}=\dfrac{-4+6}{15}=\dfrac{2}{15}\)
=>x-2/3=4/25
hay x=62/75
b: \(\Leftrightarrow x+\dfrac{1}{9}=\dfrac{2}{45}\)
=>x=2/45-1/9=2/45-5/45=-3/45=-1/15
c: \(\dfrac{17}{18}-\left(x+\dfrac{7}{12}\right)=\dfrac{1}{9}\)
=>x+7/12=17/18-1/9=17/18-2/18=15/18=5/6
=>x=5/6-7/12=10/12-7/12=1/4
d: \(\Leftrightarrow\left(x+\dfrac{13}{21}\right)\cdot\dfrac{7}{12}=\dfrac{13}{15}-\dfrac{7}{10}=\dfrac{26-21}{30}=\dfrac{1}{6}\)
=>x+13/21=1/6:7/12=1/6x12/7=12/42=2/7
=>x=2/7-13/21=-1/21
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