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Consider the following economic system:
Y = C(Y) + I(r) + G
M = L(Y, r)
where C(Y) is the consumption function, I(r) is the investment function, and L(Y, r) is the money demand function. Assume C'(Y) ∈ (0,1) for any Y > 0, I'(r) < 0 for any r > 0, and Lₓ(Y,r) > 0 and Lᵣ(Y,r) < 0 for any Y and r. Let Y*(G,M) and r*(G,M) denote the equilibrium output and interest rate, respectively.
2) Show that Y* is increasing in G and M.
(3) Show that r* is increasing in G but is decreasing in M.