a) -2(2b - 3) + 4 (3b-2) = -4b + 6 + 12b - 8 =
6 - 8 + 12b - 4b = 8b - 2;
б) 15a- (а + 3) + (2а – 1) = 15a - a - 3 + 2a - 1 = 15a - a + 2a + 1 - 3 = 16a - 2;
в) 5а – (6а – (7а – (8а - 9))) = 5a - (6a - ( 7a - 8a + 9) = 5a - (6a +a - 9) = 5a - 7a + 9 = 9 - 2a
a) -2(2b - 3) + 4 (3b-2) = -4b + 6 + 12b - 8 =
6 - 8 + 12b - 4b = 8b - 2;
б) 15a- (а + 3) + (2а – 1) = 15a - a - 3 + 2a - 1 = 15a - a + 2a + 1 - 3 = 16a - 2;
в) 5а – (6а – (7а – (8а - 9))) = 5a - (6a - ( 7a - 8a + 9) = 5a - (6a +a - 9) = 5a - 7a + 9 = 9 - 2a