Generally speaking, the x in dx is a dummy variable, meaning we can use whatever symbols we like!
In our case, the term x^(2024!) is out dummy variable. It’s what we are integrating with respect to. So how should we go about this?
Think about how we can rewrite x in terms of the term we are integrating with respect to.
It’s actually not that hard. Look :)
This is the key to the question. The two expressions are equivalent.