Resposta :
a)
[tex]3x - 2 + x = 2x + 8 \\ 4x - 2 = 2x + 8 \\ 2x - 2 = 8 \\ 2x = 10 \\ \green{x = 5}[/tex]
b)
[tex]7(x - 1) - 2(x - 5) = x - 5 \\ 7x - 7 - 2x + 10 = x - 5 \\ 5x + 3 = x - 5 \\ 4x + 3 = - 5 \\ 4x = - 8 \\ { x = - \frac {8}{4}} \\ \green {x = - 2}[/tex]