б) $$\frac{9}{16} \cdot y = -\frac{3}{8}; y = -\frac{3}{8} : \frac{9}{16} =$$

Разделим $$-\frac{3}{8}$$ на $$\frac{9}{16}$$

$$y = -\frac{3}{8} : \frac{9}{16} = -\frac{3}{8} \cdot \frac{16}{9} = -\frac{3 \cdot 16}{8 \cdot 9} = -\frac{48}{72}$$

Сократим дробь на 24

$$-\frac{48}{72} = -\frac{2}{3}$$

Ответ: $$y = -\frac{2}{3}$$