Chapter 4. Expressions, Relations, and Functions

In this chapter, you learn the fundamentals of factoring. Factoring allows you to reverse the work of the distributive property. When you factor an expression, you end up with a product. In other words, you end up with an expression that allows you to carry out a multiplication. If you carry out this multiplication, it allows you to check your work because it restores the expression to the form you started with. In addition to factoring, you investigate the notion of relations among numbers. You arrange numbers into sets based on the relationship the elements in the set have with each other. You can also use the notion of a relationship to see that numbers in a given set correspond to numbers in another set. One of the most primary relationships of this type is between the numbers in an ordered pair. An ordered pair consists of two values, one that constitutes a domain value, and the other that constitutes a range value. You can readily illustrate ordered pairs using the Cartesian coordinate system. When you generate ordered pairs in which the domain value corresponds to only one range value, then you create a function. You can test functions by using the vertical line test. Given this overview, this chapter includes the following topics of discussion:

• Factoring and the largest common factor

• The order of operations

• Cartesian coordinates and quadrants

• Expressions for functions