2. Aggregation across goods Construction direct utility function has the property that: v(p, g, w)=max U(x, Z) s.t. px+ gz Maximize u means maximize u2.Aggregation across goods • Construction direct utility function has the property that: • Maximize U means maximize u. ( , , ) max ( ) . . x v p w U x s t px w = + = , z q , z qz