Pre-Algebra Demystified

PRACTICE

Solve each of the following equations:

1. 6xþ 4 ¼2xþ 12


2. x
   10 ¼ 32
   5x


3. 9x
   5 þ2x¼ 17


4. 7x
   3 ¼4x
   27


5. 10xþ 36 ¼6x


6. 3(x
   2)¼ 24


7. 4(2x
   5)¼ 20


8. 8x
   2(3x
   7)¼ 20


9. 5(xþ6)¼ 10


10. 9(3x
    1)¼8(3x
    6)

ANSWERS

1. 2


2. 7


3. 2


4. 
   8


5. 
   9


6. 10


7. 5


8. 3


9. 
   4


10. 
    13

Algebraic Representation of Statements

In order to solve word problems in algebra, it is necessary to translate the
verbal statements into algebraic expressions. An unknown can be designated
by a variable, usually x. For example, the statement ‘‘four times a number
plus ten’’ can be written algebraically as ‘‘4xþ10.’’

EXAMPLE
Write each of the following statements in symbols:

1. the sum of a number and 15


2. seven subtracted from two times a number


3. the product of six and a number


4. three times the sum of a number and 5


5. a number divided by four

CHAPTER 7 Expression and Equations 143