1. $$\frac{m^2+n^2}{mn} \cdot \frac{m}{m+n}$$
2. При $$m=-0.8$$ и $$n=0.4$$: $$\frac{(-0.8)^2+(0.4)^2}{(-0.8)(0.4)} \cdot \frac{-0.8}{-0.8+0.4} = \frac{0.64+0.16}{-0.32} \cdot \frac{-0.8}{-0.4} = \frac{0.8}{-0.32} \cdot 2 = -2.5 \cdot 2 = -5$$
Ответ: -5