First find the slope of the linear function m =. In this problem, = 75; = 45; = 6; = 8, so m = = = -15. Thus the demand function of price x is d(x) = 75 - 15*(x-6) pounds of the chocolate moose. It is the same as d(x) = 75 + 90 - 15x = 165 - 15x. ANSWER. The demand function of the price x is d(x) = 165 - 15x pounds of the chocolate moose.