9.2. THE REAL NUMBERS
Example.
4x + 12 =
3x + 8
4x + 12 + 3x = 3x + 8 +3x
7x + 12 = 8
In transposing a term from one side to the other, just change its sign.
7x = 8 12
7x = 4
4
4
x=
=
7
7
Example.
3
x
4
3
7
2
x+ =
4
2
5
2
2 7
x=
(transposing)
3
5 2
⇣3 2⌘
4
35
x=
+
4 3
10
10
⇣9
⌘
8
39
x=
12 12
10
1
39
x=
12
10
⇣
6
39 ⌘
⇢
x=⇢
12 ⇢
10
⇢
5
x=
234
5
61