[tex] \sf Resposta: \red{\boxed{ \sf x = - \frac{1}{3}}}[/tex]
7x + 5 = 3 + x
7x + 5 - x = 3
7x - x = 3 - 5
6x = 3 - 5
6x = - 2
[tex] \sf x = - \: \frac{1}{3} [/tex]
