386. 1) (a+b)·m; 3) (3c-2d) x; 2) (a-b)·n; 4) (-5x+4y)· 2z.

Решение:

1. \( (a+b) \cdot m = am + bm \)
2. \( (3c-2d) \cdot x = 3cx - 2dx \)
3. \( (a-b) \cdot n = an - bn \)
4. \( (-5x+4y) \cdot 2z = -10xz + 8yz \)

Ответ: 1) \( am+bm \); 2) \( an-bn \); 3) \( 3cx-2dx \); 4) \( -10xz+8yz \).