The document discusses two approaches to balance-of-payments and exchange rate determination: the elasticity approach and the absorption approach. The elasticity approach emphasizes how price changes affect a nation's balance through the responsiveness of imports and exports. The absorption approach focuses on changes in real domestic income and how it compares to absorption, which is the total of consumption, investment, government spending, and imports. Both models examine how economic contractions and expansions can impact a nation's current account and currency value.