Piecewise function question.

[Zero11]

Hello everyone, I recently came across a problem while trying to plot some graphs related to a beam.
I've been able to plot piecewise functions in the hp prime so far for shear force, etc., but recently I needed to do something different. Suppose the piecewise function said 5≤X≤7, but I need it to calculate as if it were "2≤X≤0" (going the other way [from right to left] as if the 7 were equal to 0 [the starting point] and 5 were equal to 2). Is there a way I can force it to plot those values while having the graph in the 5 and 7 "positions"?