1. 5
Rational Numbers: Positive and Negative Decimals

2. R.1 Fractions
5.9 Problem Solving: Equations Containing Decimals
Objectives
Solve equations containing decimals using the addition property of equality.
Solve equations containing decimals using the division property of equality.
Solve equations containing decimals using both properties of equality.
Solve application problems involving equations with decimals.

3. Solve equations containing decimals using the addition property of equality.
Example
Solve the equation

4. Solve equations containing decimals using the addition property of equality.
Example
Solve the equation

5. Solve equations containing decimals using the division property of equality.
Example
Solve the equation

6. Solve equations containing decimals using the division property of equality.
Example
Solve the equation

7. Solve equations containing decimals using both properties of equality.
Solve the equation
Example

8. Solve equations containing decimals using both properties of equality.
Example
Solve the equation

9. Solve equations containing decimals using both properties of equality.
Example
(continued)

10. Solve application problems involving equations with decimals.
Example
Many international calling cards add a connection fee to the cost of each call. The card that Maria uses to call her sister’s cell phone in Mexico charges $0.084 per minute plus a $1.25 connection fee for each call. The cost of the call Maria made today to her sister was $5.03. How many minutes did the call last?
Step 1 Read the problem.
Unknown: number of minutes the call lasted
Known: Costs are $0.084 per minute plus $1.25 connect fee; total cost was $5.03

11. Solve application problems involving equations with decimals.
Example
(continued)
Step 2 Assign a variable: There is only one unknown, so let m be the number of minutes.
Step 3 Write an equation.

12. Solve application problems involving equations with decimals.
Example
(continued)
Step 4 Solve the equation.

13. Solve application problems involving equations with decimals.
(continued)
Example
Step 5 State the answer: The call lasted 45 minutes.
Step 6 Check the solution.
$0.084 per minute times 45 minutes = $3.78
$ $1.25 connection fee = $5.03
The cost of the call was $5.03