8. (10 points) (Estimating Utility Function) An economist in a credit card company finds that Tom only uses this company's credit cards, and his recent monthly spending details are as below, (a) Suppose the economist assumes that good 1 and good 2 are perfect complements for Tom, and his utility function is u(z,, ) = min{x,, axy}. Can this researcher find the value of a? Justify your answer. ["" Suppose the economist assumes that Tom has the Cobb-Douglas utility function of u(zy, 29) = x$ry *, where 0