1.3. Assume S = -N$200m + 0,08Y; M= 0,1Y; I = N$300m; G = N$150m; X = N$140m and t = 0,21Y. (a) Calculate the total-spending function and equilibrium income. Illustrate this on a graph. [20 marks] (b) Indicate on the graph the effect of an N$100 million increase in investment spending and comment on the magnitude of change in the equilibrium income relative to the change in investment spending. Calculate the new equilibrium income. [10 marks] (c) Assume the marginal tax changes to 0,25Y. How will this change influence the total spending curve? Illustrate this on your graph. [10 marks]