3. Решите уравнения: 1) 8 - х = 5 ; 2) +x=8 19

1) $$8 \frac{6}{19} - x = 5 \frac{3}{19}$$ $$x = 8 \frac{6}{19} - 5 \frac{3}{19}$$ $$x = (8 - 5) + (\frac{6}{19} - \frac{3}{19}) = 3 + \frac{6 - 3}{19} = 3 + \frac{3}{19}$$ $$x = 3 \frac{3}{19}$$ 2) $$\frac{6}{7} + x = 8 \frac{3}{7}$$ $$x = 8 \frac{3}{7} - \frac{6}{7}$$ $$x = 8 + \frac{3}{7} - \frac{6}{7} = 8 - \frac{3}{7} = 7 + 1 - \frac{3}{7} = 7 + \frac{7}{7} - \frac{3}{7} = 7 + \frac{7-3}{7} = 7 + \frac{4}{7}$$ $$x = 7 \frac{4}{7}$$

Ответ: 1) $$x = 3 \frac{3}{19}$$, 2) $$x = 7 \frac{4}{7}$$