In the Keynesian cross, assume that the consumption function is given by

C = 500 + 0.8 (Y - T)

Planned investment is I = 1000 - 50r

Government purchases and taxes are both 1000.

Please check my answer below, I don't if they are right or wrong. Thanks!

a Suppose that the real interest rate (r) is 5. Write the equation of the planned expenditure ( PE,). Draw planned expenditure ( PE,) as a function of income. Label this graph "figure 1".