a)
[tex]12y - (y + 5) = 10y - 1 \\ 12y - y - 5 = 10y - 1 \\ y = 4[/tex]
b)
[tex]2(u - 5) + 15 = 3(u - 4) + 10 \\ 2u - 10 + 15 = 3u - 12 + 10 \\ - u = - 2 - 5 \\ u = 7[/tex]
c)
[tex] - 3( \frac{y}{3} + 1) - 2 = 4(1 - y) \\ - y - 3 - 2 = 4 - 4y \\ 3y = 9 | \div 3 \\ y = 3[/tex]
d)
[tex]2(3a - 2) - 6 = 4.5(2a - 1) + \frac{1}{2} \\ 6a - 4 - 6 = 9a - 4.5 + \frac{1}{2} | \times 2 \\ 12a - 8 - 12 = 18a - 9 + 1 \\ - 6a = - 8 + 20 \\ - 6a = 12 | \div ( - 6) \\ a = - 2[/tex]
