1) Lecture 6 and 7 discuss the theory of consumer choice, including consumer utility, preferences, indifference curves, budget constraints, and optimal consumption bundles. 2) Consumer utility measures satisfaction from consuming goods, with marginal utility diminishing as consumption increases. Indifference curves represent bundles providing equal utility. 3) A consumer's budget constraint shows affordable combinations given income and prices. The optimal choice occurs where the highest indifference curve is tangent to the budget line.