Giải các phương trình sau:
1. a) 7x + 12 = 0 b) 5x – 2 = 0 c) 12 – 6x = 0 d) – 2x + 14 = 0
2. a) 3x + 1 = 7x – 11 b) 2x + x + 12 = 0 c) x – 5 = 3 – x d) 7 – 3x = 9 – x
e) 5 – 3x = 6x + 7 f) 11 – 2x = x – 1 g) 15 – 8x = 9 – 5
3. a) 0,25x + 1,5 = 0 b) 6,36 – 5,2x = 0