Suppose the demand for money is L = 0.20Y, the money supply is $200, C = $90 + 0.80Yd, Tx = $ 50, I = $140 - 5i an G = $50

a)Derive the IS and the LM equation,

b)Find equilibrium output, the rate of interest and investment

c)Derive the IS equation when the government spending is increases by $20, ceteris paribus.

d)Find the output, rate of interest and investment when government spending is $70