25. Incorrect. The answer is false, not true. According to the inverse function rule, if given y = f(x), the inverse function x = f^-1(y) exists, then dx/dy = (dy/dx)^-1. Therefore, since the inverse demand function P = 6 - 2Q exists, then dP/dQ = (dQ/dP)^-1 = (-0.5)^-1 = -2.