Chapter 21

Enter Mr. X: Algebra and Algebraic Expressions

In This Chapter

arrow Meeting Mr. X head-on

arrow Understanding how a variable such as x stands for a number

arrow Using substitution to evaluate an algebraic expression

arrow Identifying and rearranging the terms in any algebraic expression

arrow Simplifying algebraic expressions

You never forget your first love, your first car, or your first x. Unfortunately for some folks, remembering their first x in algebra is similar to remembering their first love who stood them up at the prom or their first car that broke down someplace in Mexico.

The most well-known fact about algebra is that it uses letters — like x — to represent numbers. So if you have a traumatic x-related tale, all I can say is that the future will be brighter than the past.

What good is algebra? That question is a common one, and it deserves a decent answer. Algebra is used for solving problems that are just too difficult for ordinary arithmetic. And because number crunching is so much a ...

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