б) $$1\frac{1}{8}-x=\frac{13}{16}$$
$$x = 1\frac{1}{8} - \frac{13}{16}$$
$$x = \frac{9}{8} - \frac{13}{16}$$
$$x = \frac{9 \times 2}{8 \times 2} - \frac{13}{16}$$
$$x = \frac{18}{16} - \frac{13}{16}$$
$$x = \frac{5}{16}$$
Ответ: $$x = \frac{5}{16}$$