ECON 1530 Lecture 8: ECON 1530 Lecture 8 Notes – Inequality signs, Quadratic Equations and Slope

• School: York University
• Department: Economics
• Course: ECON 1530
• Professor: David Kyungwon Lee

Document Summary

Econ 1530 lecture 8 notes inequality signs, quadratic equations and slope. "the last two are sometimes called weak inequality" signs: example. In economic applications, the unknown variable in an algebraic expression often represents a concept (such as quantity produced or price) that cannot normally take on a negative value. In these cases, the use of inequality signs is therefore usually more straightforward than in cases where negative values are possible. If x + 6 > y + 2 then x + 4 > y: one can multiply or divide both sides of an inequality sign by a positive number, example. If x < y then 8x < 8y (multiplying through by 8): however, if one multiplies or divides by a negative number then the direction of the inequality is reversed, example. If 3x < 18y then x > 6y (dividing both sides by 3)