When you use the distance formula does the order in which you subtract the x and y coordinates matter explain

No it does not

as long as you subtract the x's from the x's and y's from the y's

consider

and


alright, lets say x2-x1=z and x1-x2=-z
also y2-y1=t and y1-y2=-t

if we subsituted then we get


and


which simplifies to


and


the same thing
because the square of a negative becomes positive
so it doesn't matter