Ответ:

1. 45х - 54

2. 13а -114

3. 6,4х -  8

4. 9.6a + 14b - 25.2c

5. 2.7z + 10.5

6/ 1/5a - 9/5b

Пошаговое объяснение:

1. 9(7x-6)-18x = 9*7х - 9*6 - 18х = 63х - 18х - 54 = 45х - 54

2) 7a-6(19-a) = 7а - 6*19 - 6* (-а) = 7а - 114 + 6а = 13а -114

3) 0,8(6x-2)+1,6(x-4) = 0,8*6х - 0,8*2 +1,6*х - 1,6 * 4 = 4.8х - 1,6 + 1,6х - 6,4 =6,4х -  8

4. 2,8(5b-6c)-(7b-8a)*1,2 = 2,8 * 5b - 2.8* 6c - (1.2 * (7b-8a)) = 14b - 16.8c - (8.4c -  9.6a) = 14b - 16.8c - 8.4c + 9.6a = 9.6a + 14b - 25.2c

5) -(-4,9-5,8z)-(3,1z-5,6) = 4.9 +5.8z -3.1z +5.6 = 2.7z + 10.5

6. 8/15(2/1/4a-7/1/2b)-7/30(4/2/7a-8/4/7b) = 8/15 (1/2a - 7/2b) - 7/30 (2/7a - 2/7b) = 8/30a - 56/30b - 14/210a + 14/210 b = 56/210 a - 14/210 a - 392/210 b + 14/210b  = 42/210 a - 378/210 b = 1/5a - 9/5b