Pre-Algebra Demystified

SOLUTION

3xþ 12 ¼
 36


3xþ 12 
 12 ¼
 36 
12 Subtract 12


3x¼
 48


 3 x


 3

¼

48

3

Divide by
 3

x¼ 16

Check:


3xþ 12 ¼
 36


 3 ð 16 Þþ 12 ¼
 36


 48 þ 12 ¼
 36


 36 ¼
 36

PRACTICE

Solve each of the following equations:

1. 7xþ 8 ¼ 71


2. 5þ9x¼ 50


3. 6x
   3 ¼ 21


4. 
   2xþ 10 ¼ 16


5. 45
   5x¼ 50

ANSWERS

1. 9


2. 5


3. 4


4. 
   3


5. 
   1

Solving More Difficult Equations

When an equation has like terms on the same side, these terms can be

combined first.

EXAMPLE

Solve 2xþ 5 þ3x¼30.

140 CHAPTER 7 Expression and Equations