Ответ:

[tex]x \div \frac{1}{2} = 0.1 \\ \\ x \div 0.5 = 0.1 \\ x = 0.5 \times 0.1 \\ x = 0.05[/tex]

[tex]2x + 5x = 14 \\ 7x = 14 \\ x = 2[/tex]

[tex]5x - x = 19 \\ 4x = 19 \\ x = 4.75[/tex]