Я поставил за решение 65 баллов помогите плиз сложение и вычитание дробей с разными...

1.
а) $\frac{a}{6} + \frac{b}{6} = \frac{a + b}{6}$
б) $\frac{5m}{n} - \frac{3m}{n} = \frac{2m}{n}$
в) $\frac{x + 4y}{12} + \frac{2x + 5y}{12} = \frac{3x + 9y}{12} = \frac{3(x + 3y)}{12} = \frac{x + 3y}{4}$
г) $\frac{a + 2b}{2c} - \frac{a - 4b}{2c} = \frac{2a - 2b}{2c} = \frac{2(a - b)}{2c} = \frac{a - b}{c}$
д) $\frac{a - 8}{ a^{2} - 25} + \frac{13}{a^{2} - 25 } = \frac{a + 5}{(a - 5)(a + 5)} = \frac{1}{a - 5}$
е) $\frac{4b - 7c}{3b - 2c} - \frac{2b + 3c}{2c - 3b} = \frac{4b - 7c}{3b - 2c} + \frac{2b + 3c}{3b - 2c} = \frac{6b + 4c}{3b - 2c} = \frac{2(3b - 2c)}{3b - 2c} = 2$
ж) $\frac{a^{2}}{3a - 18} + \frac{36}{18 - 3a} = \frac{a^{2}}{3a - 18} - \frac{36}{3a - 18} = \frac{a^{2} - 36}{3a - 18} = \frac{(a - 6)(a + 6)}{3(a - 6)} = \frac{a + 6}{3}$
2.
$\frac{5b + 3}{b^{2} - 16 } - \frac{6b - 1}{b^{2} -16 } = \frac{-b + 4}{(b - 4)(b + 4)} = \frac{-(b -4)}{(b - 4)(b + 4)} = \frac{-1}{b + 4} = \frac{-1}{8.1} = - \frac{1}{8.1}$