1) Выполните сложение или вычитание дробей.

a) \( \frac{y}{4} + \frac{y - 2}{5} = \frac{5y + 4(y - 2)}{20} = \frac{9y - 8}{20} \) b) \( \frac{a - b}{5} + \frac{4a - b}{10} = \frac{2(a - b) + (4a - b)}{10} = \frac{6a - 3b}{10} \) c) \( \frac{2x - 1}{3} - \frac{x + 2}{6} = \frac{2(2x - 1) - (x + 2)}{6} = \frac{4x - 2 - x - 2}{6} = \frac{3x - 4}{6} \) d) \( \frac{7 - 3y}{y} - \frac{8 - 3x}{x} = \frac{x(7 - 3y) - y(8 - 3x)}{xy} = \frac{7x - 3xy - 8y + 3xy}{xy} = \frac{7x - 8y}{xy} \) e) \( \frac{m - n}{m^2} - \frac{n - m}{mn} = \frac{(m - n)n - (n - m)m}{m^2n} = \frac{mn - n^2 - nm + m^2}{m^2n} = \frac{m^2 - n^2}{m^2n} \) f) \( \frac{3x + 2}{5x} - \frac{5x + 3y}{10xy} - \frac{y - 1}{2y} = \frac{2(3x + 2)y - (5x + 3y)x - 5x(y - 1)}{10xy} = \frac{6xy + 4y - 5x^2 - 3xy - 5xy + 5x}{10xy} = \frac{-5x^2 - 2xy + 5x + 4y}{10xy} \)