m81319 Introduction to Solving Linear Equations 200deaa1-ff02-40e4-acae-5b045668e591

A Calder mobile is balanced and has several elements on each side. (credit: paurian, Flickr)

Teetering high above the floor, this amazing mobile remains aloft thanks to its carefully balanced mass. Any shift in either direction could cause the mobile to become lopsided, or even crash downward. In this chapter, we will solve equations by keeping quantities on both sides of an equal sign in perfect balance.