Recall the Keynesian Cross is the foundation to derive the IS curve. Suppose we have a simple closed economy. The cross of planned expenditure (PE) and the equilibrium condition (PE = Y) of this economy shows the equilibrium level of national output in the goods market. Here we assume the consumption (C) is a function of • C = 120 + 0.75(Y-T); Here the marginal propensity to consume (MPC) equals 0.75. Planned investment (I) is 200; government purchases (G) and taxes (T) are both 400. Use the conditions given, finish the following questions. (1) What is the equilibrium level of national income? Show step-by-step solution. Tip: recall the definition of planned expenditure (PE). At equilibrium, actual expenditure (Y) equals planned expenditure. (2) If government expenditures increase to 500, ceteris paribus (other things being equal), what is the new equilibrium income? What is the multiplier for government purchases? How much is the change of national income from the increase in government purchases (G)? Tip: recall the multiplier for government purchase in your notes (slides).   (3) If government cut tax to 300, how much is the new equilibrium income (ceteris paribus)? How much is the tax multiplier? How much is the change of national income from the tax cut? Tip: recall the multiplier for tax policy in your notes (slides).