Another way to think about it is, we could have rewritten this thing. So this is equal to e to the negative four x dx. This is exactly what our problem is, what we need to take the definite integral. And so that it becomes completely clear so that the derivative of this thing is sitting around here. We could put a negative four over here. But you can't just willy nilly throw a negative four there. You would have to put a negative 1 4th outside of it in order for it to be, in order negative 1 4th times negative four, you're just multiplying by one, which doesn't change the value.