You are given the following information on the macro economy (in millions dollars):
Consumption: 250 + 0.60Y
Investment: 100 + 0.35Y
Government Spending: 400
Exports: 50
Imports: 50 + 0.20Y
Compute the equilibrium level of income, the size of the multiplier, and the change in equilibrium income for a decrease in autonomous investment by $75 million. Show your work.