The demand for video recorders has been estimated to be Qv = 134 − 1.07Pf + 46Pm − 2.1Pv − 5I, where Qv is the quantity of video
recorders, Pf denotes the price of video recorder film, Pm is the price of attending a movie, Pv is the price of video recorders, and I is income. Based on the estimated demand equation we can conclude: the demand for video recorders is neither inferior nor inelastic, and video recorder film is not a substitute for video recorders.
video recorder film is a substitute for video recorders.
The price of the recorders films are increasing by a term 1.07 which gives that the Price is increasing by a little. Also adding the Price of video recorder is increasing by a factor 2.1 and the Revenue or income is increasing by a term 5 (Which is high) so, revenue and price are increasing leaving the quality of the voice recorder decreasing by a large margin for maintaining the balance.
As
So, in conclusion the quality decreases and thus the video recorders are inferior goods.