Resposta:
[tex] \frac{20}{5} = \frac{x}{5} \\ \\ 5x = 100 \div (5) \\ x = 20[/tex]
[tex] \frac{1}{7} = \frac{x - 6}{49} \\ \\ 7 \times (x - 6) = 49 \\ 7x - 42 = 49 \\ 7x - 42 - 49 = 0 \\ 7x - 91 = 0 \\ 7x = 91 \div (7) \\ x = 13[/tex]
[tex] \frac{2}{5} = \frac{x}{200} \\ \\ 5x = 400 \div (5) \\ x = 80[/tex]
