1. 2
Understanding Variables and Solving Equations

2. R.1 Fractions
2.3 Solving Equations Using Addition
Objectives
Determine whether a given number is a solution of an equation.
Solve equations using the addition of equality.
Simplify equations before using the addition property of equality.

3. Determine whether a given number is a solution of an equation.
An equation has an equal sign.

4. Determine whether a given number is a solution of an equation.
We solve an equation by finding a number that can replace the variable and make the equation balance.

5. Which of 70, 40, and 60 is the solution of the equation c – 10 = 50?
Determine whether a given number is a solution of an equation.
Which of 70, 40, and 60 is the solution of the equation c – 10 = 50?
Example

6. Solve equations using the addition property of equality.

7. Solve equations using the addition property of equality.

8. Solve the equation c + 5 = 30. Check the solution. Example
Solve equations using the addition property of equality.
Solve the equation c + 5 = 30. Check the solution.
Example
Keep the balance, add –5 to the right side also.

9. (continued) Check the solution. Example
Solve equations using the addition property of equality.
(continued) Check the solution.
Example

10. Solve the equation –5 = x – 3. Check the solution. Example
Solve equations using the addition property of equality.
Solve the equation –5 = x – 3. Check the solution.
Example

11. (continued) Check the solution. Example
Solve equations using the addition property of equality.
(continued) Check the solution.
Example

12. Simplify equations before using the addition property of equality.
Solve the equation –2 + 2 = –4b – 6 + 5b. Check the solution.
Example

13. Simplify equations before using the addition property of equality.
(continued) Check:
Example