$\frac{1}{2}$- $\frac{1}{5}$ + $\frac{3}{5}$ × x=4
=> $\frac{1}{2}$ + $\frac{3}{5}$ .x=4 + $\frac{1}{5}$
=> $\frac{1}{2}$ + $\frac{3}{5}$.x= $\frac{21}{5}$
=> $\frac{3}{5}$.x= $\frac{21}{5}$ -$\frac{1}{2}$
=> $\frac{3}{5}$× x= $\frac{37}{10}$
=> x= $\frac{37}{10}$ ÷ $\frac{3}{5}$
=> x= $\frac{37}{10}$ . $\frac{5}{3}$
=> x = $\frac{37}{6}$
Vậy x= {$\frac{37}{6}$ }
