\(a,x+\left(\dfrac{-2}{5}\right)=\dfrac{-2}{15}\)
\(x=\dfrac{-2}{15}+\dfrac{2}{5}\)
\(x=\dfrac{-2}{15}+\dfrac{6}{15}\)
\(x=\dfrac{4}{15}\)
Vậy ......
\(b,3\dfrac{3}{30}-x=0,9\)
\(\dfrac{31}{10}-x=\dfrac{9}{10}\)
\(x=\dfrac{31}{10}-\dfrac{9}{10}\)
\(x=\dfrac{22}{10}\)
\(x=\dfrac{11}{5}\)
Vậy .....
\(c,\dfrac{3}{8}-\left(\dfrac{1}{2}-x\right)=\dfrac{5}{4}\)
\(\dfrac{1}{2}-x=\dfrac{3}{8}-\dfrac{5}{4}\)
\(\dfrac{1}{2}-x=\dfrac{3}{8}-\dfrac{10}{8}\)
\(\dfrac{1}{2}-x=\dfrac{-7}{8}\)
\(x=\dfrac{1}{2}-\dfrac{-7}{8}\)
\(x=\dfrac{4}{8}+\dfrac{7}{8}\)
\(x=\dfrac{11}{8}\)
Vậy ......
\(d,\dfrac{2}{5}+\dfrac{5}{3}x=\dfrac{5}{7}\)
\(\dfrac{5}{3}x=\dfrac{5}{7}-\dfrac{2}{5}\)
\(\dfrac{5}{3}x=\dfrac{25}{35}-\dfrac{14}{35}\)
\(\dfrac{5}{3}x=\dfrac{11}{35}\)
\(x=\dfrac{11}{35}:\dfrac{5}{3}\)
\(x=\dfrac{11}{35}.\dfrac{3}{5}\)
\(x=\dfrac{33}{175}\)
Vậy ....
\(e,\dfrac{7}{3}x+\dfrac{4}{7}=\dfrac{-3}{7}\)
\(\dfrac{7}{3}x=\dfrac{-3}{7}-\dfrac{4}{7}\)
\(\dfrac{7}{3}x=\dfrac{-7}{7}\)
\(\dfrac{7}{3}x=-1\)
\(x=-1:\dfrac{7}{3}\)
\(x=-1.\dfrac{3}{7}\)
\(x=\dfrac{-3}{7}\)
Vậy ....