David consumes two things: gasoline (9) and bread (92). David's utility function is 0.5 0.5 U(91, 92)=409192 Let the price of gasoline be p, the price of bread be p2, and income be Y. Derive David's demand curve for gasoline. David's demand for gasoline is 9 = . (Properly format your expression using the tools in the palette. Hover over tools to see keyboard shortcuts. E.g., a subscript can be created with the _ character.)