193. Раскройте скобки и приведите подобные слагаемые: 1) 9(7x – 6) – 18x; 2) 7а – 6(19 – a); 3) 0,8(6x – 2) + 1,6(x - 4); 4) 2,8(5b – 6a) – (7b – 8a) 1,2; 5) -(-4,9 – 5,8c) – (3,1c – 5,6); 6) 8/9 (2 1/4 a - 3/4 b) - 7/30 (4 2/7 a - 8/7 b).

1) $$63x - 54 - 18x = 45x - 54$$
2) $$7a - 114 + 6a = 13a - 114$$
3) $$4.8x - 1.6 + 1.6x - 6.4 = 6.4x - 8$$
4) $$14b - 16.8a - 8.4b + 9.6a = -7.2a + 5.6b$$
5) $$4.9 + 5.8c - 3.1c + 5.6 = 2.7c + 10.5$$
6) $$8/9 * (9/4 a - 3/4 b) - 7/30 * (30/7 a - 8/7 b) = 2a - 6/12 b - 2a + 56/210 b = -1/2 b + 4/15 b = (-15 + 8)/30 b = -7/30 b$$