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