With the form f(x+a) the vertex of the parabola will be shifted to left with a>0 and to the right with a<0. The larger the magnitude of a the more shift. So we can simply sort by the value a in descending order:
f(x+3)-->f(x+2)-->f(x)-->f(x-1/2)-->f(x-4)-->f(x-7)
