After combining like terms to simplify the equation: 3 - 15x + 24 + 16x = 4x - 24 - 4x , what would be the best next step to finish solving?

The best next step to finish solving would be to simplify the right side of the equation by combining like terms:

4x - 24 - 4x = -24
Therefore, the equation simplifies to:
3 + x = -24