Respuesta :

Answer:

12x + 15 = 12x - 15 can not be solved.

We can not find out what x equals.

Step-by-step explanation:

You can solve - 5x - 25 = 5x + 25

x = - 5

You can solve 7x + 21 = 21

x = 0

You can solve 12x + 15 = 3(4x + 5)

x = AllRealNumbers

That leaves 12x + 15 = 12x - 15

This equation can not be solved