i think I solved it I just want to know if it is right
a. P=120-1.25q, to get the quantity when the price is 80, just represent P with 80 in the equation:
80=120-1.25q
80+1.25q=120
1.25q=120-80
1.25q=40
q=40/1.25
q=32. The quantity demanded when the price is $80.
b. To get the price...