a)
[tex]3(x - 5) + x = 2 - x \\ 3x - 15 + x = 2 - x \\ 5x = 17 | \div 5 \\ x = \frac{17}{5} \\ x = 3 \frac{2}{5} [/tex]
b)
[tex]x + \frac{2}{3} + x = 3 - 2x | \times 3 \\ 3x + 2 + 3x = 9 - 6x \\ 12x = 7 | \div 12 \\ x = \frac{7}{12} [/tex]
c)
[tex]4 - 2x - \frac{5}{2} = 3 - x \\ 4 - 2x - 2.5 = 3 - x \\ - x = 1.5 | \times ( - 1) \\ x = - 1.5[/tex]