Answer:
Step-by-step explanation:
Slope of Expenditure line = Marginal propensity to consume (MPC) + Marginal propensity to invest (MPI) + Marginal propensity to government purchases (MPG) - Marginal propensity to import (MPM).
Here, MPC = 0.8. But, since planned investment, government purchases and net exports (= Exports - Imports) are both fixed values, this means investment, government purchases and net exports (including imports) are autonomous expenditures, and therefore,
MPI = 0, MPG = 0 and MPM = 0.
Slope of expenditure line = MPC = 0.8