Вычитание дробей

1. а) $$rac{a}{6} + rac{b}{6} = rac{a + b}{6}$$
2. б) $$rac{p}{3} - rac{q}{3} = rac{p - q}{3}$$
3. в) $$rac{x}{y} + rac{3x}{y} = rac{x + 3x}{y} = rac{4x}{y}$$

2. $$rac{5m}{n} - rac{3m}{n} = rac{5m - 3m}{n} = rac{2m}{n}$$

3. g) $$rac{x + 4y}{12} + rac{2x + 5y}{12} = rac{x + 4y + 2x + 5y}{12} = rac{3x + 9y}{12} = rac{3(x + 3y)}{12} = rac{x + 3y}{4}$$