a)
[tex]3 - 2(x + 1) = 7 \\ 3 - 2x - 1 = 7 \\ - 2x = 5 | \div ( - 2) \\ x = - \frac{5}{2} \\ x = - 2.5[/tex]
b)
[tex] \frac{2}{3} (5x + 1) = 4 \\ \frac{10}{3} x + \frac{2}{3} = 4 | \times 3 \\ 10x + 2 = 12 \\ 10x = 10 | \div 10 \\ x = 1[/tex]
c)
[tex]2x - \frac{x + 1}{3} = x - 1 | \times 3 \\ 6x - x - 1 = 3x - 3 \\ 2x = - 2 | \div 2 \\ x = - 1[/tex]
