3.1 Graph a typical indifference curve for the following utility functions, and determine whether they have convex indifference carryes (i.e., whether the MRS declines as x increases). a. U(x, y) = 3x + y. b. U (x, y ) = x . y. - U(x, y) = v xty d U(x, y) = Vx - yz xy # U(x, y) x+y