\(\frac{-4}{12} = -\frac{1}{3}\)
\(\frac{a}{1} \cdot \frac{x^2}{x} \cdot \frac{1}{y} = a \cdot x \cdot \frac{1}{y} = \frac{ax}{y}\)
\(-\frac{1}{3} \cdot \frac{ax}{y} = -\frac{ax}{3y}\)
Ответ: \(-\frac{ax}{3y}\)