Macroeconomics 13th Edition by William Baumol ,Alan Blinder

Exercise 10

Referring to Test Yourself Question 1, do the same for an economy in which investment is $250, net exports are zero, government purchases and taxes are both $400, and the consumption function is as follows:
C = 250 + 0.5 DI
Reference Test Yourself Question 1,
Find the equilibrium level of GDP demanded in an economy in which investment is always $300, net exports are always -$50, the government budget is balanced with purchases and taxes both equal to $400, and the consumption function is described by the following algebraic equation:
C = 150 + 0.75 DI
( Hint: Do not forget that DI = Y - T. )