Problem 1 (2 points): Consider the macroeconomic model defined by National income: Y=C+I+G* (G* > 0) Consumption: C=aY+b (00) Investment: I = cr + d (c<0, d > 0) Money supply: M,* = k₁Y+k₂r (k> 0, k.< 0, M,* > 0) Show that this system can be written as Ax=b, where 1 -1 0 G 1 0 0 b A and b 0 0 1 k₁ 0 0 k₂] M a/ Use Cramer's rule to find I; b/ Write down the government expenditure multiplier for I and deduce it's meaning.