2/3 (x - 1) - 4/5 (3 - 2x) = x + 9

a) 2/3 ( x - 1) - 4/5 ( 3 - 2x ) = x + 9 b) x - 1/12 = 75/x - 1 c) 7^x - 1 + 7^x + 1 - 7^x . 2 = 1764