A Large Open Economy Has Desired National Saving of S^d

Essay

A large open economy has desired national saving of S^d = 20 + 200r^w,and desired national investment of I^d = 30 - 200r^w.The foreign economy has desired national saving of = 40 + 100r^w,and desired national investment of = 75 - 400r^w.
(a)Calculate the equilibrium values of r^w,CA,CA_For,S,I,S_For,and I_For.
(b)Suppose S^d rises by 45,so that now S^d = 65 + 200r^w.Calculate the equilibrium values of r^w,CA,CA_For,S,I,S_For,and I_For.
(c)Suppose,with S^d back to S^d = 20 + 200r^w,as in part (a),that I^d rises by 45,to I^d = 75 - 200r^w.Calculate the equilibrium values of r^w,CA,CA_For,S,I,S_For,and I_For.