1) 7а - 9b = 7a - 9b =
49a²-63ab 49a²-81b² 7a(7a-9b) (7a-9b)(7a+9b)
= 1 - 9b = 7a+9b-9b = 7a
7a-9b (7a-9b)(7a+9b) (7a-9b)(7a+9b) 49a²-81b²
2) 6a - b = 6a - b =
36a²-6ab 36a²-b² 6a(6a-b) (6a-b)(6a+b)
= 1 - b = 6a+b-b = 6a
6a-b (6a-b)(6a+b) (6a-b)(6a+b) 36a²-b²