Г. Сложение и вычитание дробей с разными знаменателями
Задание 6. Выполните действие:
- \( \frac{2}{a} + \frac{2}{a-2} = \frac{2(a-2)}{a(a-2)} + \frac{2a}{a(a-2)} = \frac{2a-4+2a}{a(a-2)} = \frac{4a-4}{a(a-2)} \)
- \( \frac{1}{a-2} + \frac{b}{2-a} = \frac{1}{a-2} - \frac{b}{a-2} = \frac{1-b}{a-2} \)
- \( \frac{m}{8} + \frac{y-b}{8} = \frac{m+y-b}{8} \)
- \( \frac{5x}{5} - \frac{2x}{5} = \frac{5x-2x}{5} = \frac{3x}{5} \)
- \( \frac{b}{y^2} - \frac{b-a}{y^2} = \frac{b-(b-a)}{y^2} = \frac{b-b+a}{y^2} = \frac{a}{y^2} \)
- \( \frac{a+5}{a} + \frac{4}{a} = \frac{a+5+4}{a} = \frac{a+9}{a} \)
- \( \frac{x^2+2}{2} + \frac{2}{y-5} = \frac{(x^2+2)(y-5)}{2(y-5)} + \frac{2 \times 2}{2(y-5)} = \frac{x^2y-5x^2+2y-10+4}{2(y-5)} = \frac{x^2y-5x^2+2y-6}{2(y-5)} \)
- \( \frac{3a}{2b-5} + \frac{4a}{5-2b} = \frac{3a}{2b-5} - \frac{4a}{2b-5} = \frac{3a-4a}{2b-5} = \frac{-a}{2b-5} \)
- \( \frac{2}{a-1} - \frac{4}{a+1} = \frac{2(a+1)}{(a-1)(a+1)} - \frac{4(a-1)}{(a-1)(a+1)} = \frac{2a+2 - (4a-4)}{(a-1)(a+1)} = \frac{2a+2-4a+4}{(a-1)(a+1)} = \frac{-2a+6}{(a-1)(a+1)} \)
- \( \frac{b}{x-3} + \frac{a}{x+3} = \frac{b(x+3)}{(x-3)(x+3)} + \frac{a(x-3)}{(x-3)(x+3)} = \frac{bx+3b+ax-3a}{(x-3)(x+3)} \)