Which of the following equations has exactly one solution?

3x - 7 = 3x - 7
3x - 7 = 3x - 5
3x - 7 = -3x - 7
3x + 7 = 3x - 7
-3x + 5 = -3x + 7

1 answer

3x - 7 = 3x - 7