[tex] 1 - \frac{1}{5} \times x = 0.5[/tex]
[tex]1 - \frac{x}{5} = \frac{5}{10} [/tex]
[tex]1 - \frac{x}{5} = \frac{1}{2} [/tex]
[tex] \frac{10}{10} - \frac{2x}{10} = \frac{5}{10} [/tex]
[tex]10 - 2x = 5[/tex]
[tex] - 2x = 5 - 10[/tex]
[tex] - 2x = - 5 \: | \times ( - 1)[/tex]
[tex]2x = 5[/tex]
[tex]x = \frac{5}{2} [/tex]
