Which of the following are true of the expenditure multiplier concept? Select the correct answer below: It is the concept that increasing national income affects the equilibrium level of GDP on par with the amount of increased income. It is the idea that decreasing national income affects the equilibrium level of GDP by the same amount of that decrease in income. It is the concept that an increase in spending causes a more than proportionate change in GDP. The expenditure multiplier is the idea that a given change in spending leads to an equal change in the equilibrium level of GDP.

David consumes two things: gasoline (g) and bread (b). david's utility function is u(g, b) = 10g^0.25 b^0.75. use the lagrange technique to solve for david's optimal choices of gasoline and bread as a function of the price of gasoline, p_g, the price of bread, p_b, and his income m. with recent decrease in the price of gasoline (maybe due to external shock such as shale gas production) does david increase his consumption of gasoline? for david, how does partial differential g/partial differential p_g depend on his income m? that is, how does david's change in gasoline consumption due to an increase in the price of gasoline depend on his income level? to answer these questions, find the cross-partial derivative, |partial differential^2 g/partial differential m partial differential p_g.