Answer:
y=2.5x - Proportional
y= x - 4 - Not Proportional
Step-by-step explanation:
A linear function that is proportional is in the form y =kx (k is the constant of variation) and passes the origin.
The first equation given is in this form (2.5 is the constant) and it passes through the origin. It is proportional.
However, the second one is not proportional is it does not pass the orgin and it's not in y=kx form.
Hope this helps.
