Question

номер 760 пример2,4,6

Answer 1

5,7а - 8 - а=4,7а - 8

7-3,8b-9b=7 - 12.8b

15c+3-2.9c=12.1c+3

Answer 2

5,7a-8-a=(5,7-1)a-8=4,7a-8;
7-3,8b-9b=7-(3,8+9)b=7-12,8b;
15c+3-2,9c=(15-2,9)c+3=12,1c+3.