Math Word Problems Demystified - A Self Teaching Guide

parentheses. For example,

3 ðxþ 2 Þ¼ 3 xþ 3  2 ¼ 3 xþ 6

5 ð 2 x
 8 Þ¼ 5  2 x
 5  8 ¼ 10 x
 40

When you solve an equation, remove parentheses first, combine like terms
(i.e., 6xþ 8 x), and then solve as shown in the previous examples.

EXAMPLE:Solve forx: 2(3x
12)¼ 36

SOLUTION:

2 ð 3 x
 12 Þ¼ 36

2  3 x
 2  12 ¼ 36 remove parentheses

6 x
 24 ¼ 36

6 x
 24 þ 24 ¼ 36 þ24 add 24

6 x¼ 60

61 x

61

¼

60

6

divide by 6

x¼ 10

EXAMPLE:Solve forx: 5(3xþ8)
10 x¼ 35

SOLUTION:

5 ð 3 xþ 8 Þ
 10 x¼ 35

15 xþ 40 
 10 x¼ 35 remove parentheses

5 xþ 40 ¼ 35 combine 15x
 10 x

5 xþ 40 
 40 ¼ 35 
40 subtract 40

5 x¼
 5

51 x

51

¼

5

5

divide by 5

x¼
 1

REFRESHER IV Equations 75