Ответ:

Пошаговое объяснение:

№1

1) 4,2a ⋅ (-1,8) ⋅ (-2,5n) = 18,9an

   коефіцієнт - 18,9;

2) 2 5/8х ⋅ (-16/63)у = - 21/8 ⋅ 16/63 ху = -2/3 ху

   коефіцієнт - -2/3.

№2

1) 20 ⋅ 2 - 30 ⋅ 2 = 2 ⋅ (20 - 30) = 2 ⋅ (-10) = -20;

2) - 3 ⋅ 9 - 4 ⋅ 9 = 9 ⋅ (- 3 - 4) = 9 ⋅ (-7) = -63;

3) 4 ⋅ (1/4 - 1) = 4 ⋅ (1/4 - 4/4) = 4 ⋅ (-3/4) = -3.