[tex]\sf \longmapsto \frac{1}{5} x + \frac{1}{2} > \frac{4}{5} [/tex]
[tex]\sf \longmapsto \frac{1}{5} x + \frac{1}{2} - \blue{\frac{1}{2 }}> \frac{4}{5} - \blue{ \frac{1}{2} }[/tex]
[tex]\sf \longmapsto \frac{1}{5} x > \frac{3}{10} [/tex]
[tex]\sf \longmapsto5 \times ( \frac{1}{5} x) > 5 \times ( \frac{3}{10} )[/tex]
[tex]\sf \longmapsto x > \frac{3}{2} [/tex]
[tex] \boxed{\sf \: x > \frac{3}{2} }[/tex]
