i am trying to transform a piece wise function, but my problem is that the lines are so irregular i cant tell if it is correct. i can't even tell the equation of the lines I'm attempting to transform.

y= -2/3 x -6 if -9<=x<-6
y= 1/3 x if -6<=x<0
then the problematic part:
an ellipse with 5 points i can discern:
(0,0) (1,3) (3,4) (5,3) (6,0)

the transformation i have to graph is:

y=1/2 f((2x)/3)

could you please help me figure out how to graph this? i keep trying to solve it but i feel as though i am doing it incorrectly.