Giải các phương trình bậc hai sau:
- x2 – 3x + 2 = 0
- x2 – 3x – 4 = 0
- x2 – 5x + 6 = 0
- x2 – 5x – 6 = 0
- x2 + 5x – 6 = 0
- x2 + 5x + 4 = 0
- x2 – 7x +12 = 0
- x2 – 7x – 8 = 0
- x2 – 9x + 20 = 0
- x2 – 6x + 8 = 0
- x2 – x – 30 = 0
- x2 – (2m-1)x -m2 -42m +1 = 0 (Khi m = 1)
- x2 – 2x – m = 0 (Khi m = 8)
- x2 – 7x + m = 0 (Khi m = 10)
- x2 – 2mx + m2 – 1= 0 (m = 4)
