The first one means (dx) all squared, the other means delta * x^2
So unless delta is just a word meaning something, and doesn't hold a value, then they are both different.
If is simply another variable, then your question has already been answered. However if you were asking if where dx is a differential, then this is sometimes the case. You'll find that in many books (especially physics books) a squared differential is sometimes denoted as dx^2 rather than (dx)^2, or at least that is the case in my experience. If this is the case, then they are the same.