Final answer:
According to Keynesian macroeconomics, an increase in government spending leads to a decrease in private investment and government debt.
Step-by-step explanation:
According to Keynesian macroeconomics, an increase in government spending leads to a decrease in a) private investment and b) government debt. In contrast to microeconomics, where increased government spending can lead to increased private investment, in macroeconomics, excessive government spending can crowd out private investment in physical capital, slowing down economic growth. Additionally, sustained large budget deficits can lead to negative macroeconomic outcomes such as inflation and a dependence on foreign financial investment.