Решение:
\[\frac{y}{x^2-y^2}: \frac{y}{x^2+xy} = \frac{y}{x^2-y^2} \cdot \frac{x^2+xy}{y} = \frac{x(x+y)}{(x-y)(x+y)} = \frac{x}{x-y}\]
\[\frac{1.2}{1.2-0.4} = \frac{1.2}{0.8} = 1.5\]
Ответ: 1,5.