They are 3 terms of an algebraic expression
12a + 6b + 9a + 14b =(12a + 9a) + (6b + 14b) =21a + 20b
b^2 + 8b + 7 factors to (b + 7)(b + 1)
8b = e - 12n, possibly.
8b = -65 so b = -8.125
6B, 7B, 8B, 9B, 10B, 11B, 12B, 13B, 14B, 15B, 16B, 17B, 18B, 19B
6B, 7B, 8B, 9B, 10B, 11B, 12B, 13B, 14B, 15B, 16B, 17B, 18B, 19B
8b
13b !
8b^2 -9b +1 8b^2 -8b -b +1 8b(b-1) - 1(b-1) (8b-1)(b-1)
6a + (7b - 4a - 8b) = (6a - 4a) + (7b - 8b) = 2a - b
8b + 11 - 3b = 2b + 2 5b + 11 = 2b + 2 5b - 2b = 2 - 11 3b = -9 b = -3