Consider an economy in which households consume 90, regardless of their income, and an additional 75 cents of each additional dollar of income earned. Firms invest 50. Write an expression for aggregate expenditure as a function of income. Simplify your answer and write in all caps and without any spaces (e.g. AE=A+BY). There is a wave of optimism and firm investment rises to 60. Write a new expression for aggregate expenditure as a function of income