Functions are a key concept in algebra. A function describes a relationship and allows you to predict future outcomes. Most of the technology we take for granted, from automobiles and CD players to medical procedures and microchips, has been made possible because someone first used functions to make predictions.

In this chapter you will: build on your knowledge of functions learned in Chapter 2 learn to solve simple equations learn to solve one- and two-step equations use one- and two-step equations to solve real-world problems learn to use the distributive property learn to combine like terms to solve equations solve equations involving rational numbers learn how to use equations to find the probability of dependent and independent events use equations to find percents and percent of change