4. Решите уравнение: a) y-2\frac{1}{5}=5\frac{2}{5}; 13 10 2 6) (x-3)+2=7.

a) $$y - 2 \frac{1}{5} = 5 \frac{2}{5}$$

$$y = 5 \frac{2}{5} + 2 \frac{1}{5}$$

$$y = 7 \frac{3}{5}$$

Ответ: $$7 \frac{3}{5}$$

б) $$(x - 3 \frac{13}{21}) + 2 \frac{10}{21} = 7 \frac{2}{21}$$

$$x - 3 \frac{13}{21} = 7 \frac{2}{21} - 2 \frac{10}{21}$$

$$x - 3 \frac{13}{21} = 6 \frac{23}{21} - 2 \frac{10}{21}$$

$$x - 3 \frac{13}{21} = 4 \frac{13}{21}$$

$$x = 4 \frac{13}{21} + 3 \frac{13}{21}$$

$$x = 7 \frac{26}{21}$$

$$x = 8 \frac{5}{21}$$

Ответ: $$8 \frac{5}{21}$$