Question

Answer 1

\(\dfrac{-1}{10}+\dfrac{2}{5}x+\dfrac{7}{20}=\dfrac{1}{10}\)
\(\dfrac{2}{5}x+\dfrac{7}{20}=\dfrac{1}{10}-\dfrac{-1}{10}\)
\(\dfrac{2}{5}x+\dfrac{7}{20}=\dfrac{2}{10}\)
\(\dfrac{2}{5}x+\dfrac{7}{20}=\dfrac{1}{5}\)
\(\dfrac{2}{5}x=\dfrac{1}{5}-\dfrac{7}{20}\)
\(\dfrac{2}{5}x=\dfrac{4}{20}-\dfrac{7}{20}\)
\(\dfrac{2}{5}x=\dfrac{-3}{20}\)
\(x=\dfrac{-3}{20}:\dfrac{2}{5}\)
\(x=\dfrac{-3}{20}.\dfrac{5}{2}\)
\(x=\dfrac{\left(-3\right).1}{4.2}\)
\(x=\dfrac{-3}{8}\)
Vậy \(x=\dfrac{-3}{8}\)
 

Answer 2

\(\dfrac{-1}{10}+\dfrac{2}{5}.x+\dfrac{7}{20}=\dfrac{1}{10}\\ \dfrac{2}{5}x=\dfrac{2}{10}-\dfrac{7}{20}\\ \dfrac{2}{5}x=\dfrac{-3}{20}\\ x=\dfrac{-3}{20}:\dfrac{2}{5}\\ x=\dfrac{-3}{8}\\\)

Vậy ...