Pre-Algebra Demystified

EXAMPLE

Simplify 5(2xþ3)
6.

SOLUTION

5 ð2xþ 3 Þ
 6 ¼10xþ 15 
 6 Remove parentheses

¼10xþ 9 Combine like terms

EXAMPLE

Simplify
2(xþ7y)þ6x.

SOLUTION

 2 ðxþ7yÞþ6x¼
2x
14yþ6x Remove parentheses

¼ 4x
14y Combine like terms

PRACTICE

Simplify each of the following expressions:

1. 7(xþ2)þ 8


2. 3(2xþ3y
   5)þ6x
   3


3. 
   2(4aþ6b)
   2aþ3b


4. 5(aþ2b
   c)þ6a


5. 9(xþ2y)þ4(x
   6y)

ANSWERS

1. 7xþ 22


2. 12xþ9y
   18


3. 
   10a
   9b


4. 11aþ10b
   5c


5. 13x
   6y

Formulas

In mathematics and science, many problems can be solved usingformulas.A
formulais a mathematical statement of a relationship of two or more vari-
ables. For example, the relationship between Fahrenheit temperature and
Celsius temperature can be expressed by the formula F ¼^95 C þ 32 o.
Formulas can be evaluated in the same way as expressions are evaluated:

CHAPTER 7 Expression and Equations 133