\(0,75.x-\frac{2}{5}.x=\frac{7}{20}\)
=> \(\frac{3}{4}.x-\frac{2}{5}.x=\frac{7}{20}\)
=> \(x\left(\frac{3}{4}-\frac{2}{5}\right)=\frac{7}{20}\)
=> \(x.\frac{7}{20}=\frac{7}{20}\)
=> x=1
\(\frac{3}{4}-\frac{2}{5}=\frac{15}{20}-\frac{8}{20}=\frac{7}{20}\)
nha bạn