3A.a.X is an inferior good since the estimated coefficient on ln M, the income elasticity, is negative (0.05152).b. X and Y are substitutes since the estimated coefficient on ln PY , the cross-price elasticity, is positive (0.35).c. (Note: 15,670,175 = e16.56727.)d. For all values of P, M, PY, the elasticity estimates are constant and equal to = 2.85, = 0.05152, and = 0.35. Estimated Q: .