The answer is infinitely many solutions because 0 = 0.
If you don't seem to see where I got 0 = 0, look at the equation,
4b – 4b = 0
first lets do the math on the left side.
4b - 4b is equal to 0.
so lets put 0 on the left side, now lets look at the equation all together,
0 = 0,
and this means that it has infinitely many solutions.
The reason why it is not no solution because no solution means when there are no answers to the equation. For example, the solution is not true, such as the equation 24 ≠ 29. This is a no solution equation. One solution can be 4x = 20, as x = 5, concluding it being one solutions.