#
Section 1-1

#
Solving One-Step Equations: Addition and Subtraction

Some
linear equations
can be solved with a single operation. For this type
of equation, use the
inverse
operation
to solve. The easiest type involves only an addition or a subtraction.

**
Example 1:
**

Solve for
*
n
*
:
**
**

*
n
*
+ 8 = 10

The inverse operation of addition is subtraction. So, subtract 8 from both
sides. (The
Subtraction
Property of Equality
assures us that the two sides will still be the same.)

**
***
n
*
+ 8 – 8 = 10 – 8

**
***
n
*
= 2
**
**

**
Example 2:
**

Solve for
*
y
*
:

**
***
y
*
– 11 = –15

The inverse operation of subtraction is addition. So, add 11 to both sides.
(Here we're using the
Addition
Property of Equality
.)

*
***
y
**
**
– 11 + 11 = –15 + 11
**

*
***
y
**
**
= –4
**