## Key Concepts

**Determine whether a number is a solution to an equation.**- Substitute the number for the variable in the equation.
- Simplify the expressions on both sides of the equation.
- Determine whether the resulting equation is true. If it is true, the number is a solution.

If it is not true, the number is not a solution.

**Subtraction Property of Equality**- For any numbers [latex]a[/latex] , [latex]b[/latex] , and [latex]c[/latex] ,

if [latex]a=b[/latex] then [latex]a-b=b-c[/latex]

- For any numbers [latex]a[/latex] , [latex]b[/latex] , and [latex]c[/latex] ,
**Solve an equation using the Subtraction Property of Equality.**- Use the Subtraction Property of Equality to isolate the variable.
- Simplify the expressions on both sides of the equation.
- Check the solution.

**Addition Property of Equality**- For any numbers [latex]a[/latex] , [latex]b[/latex] , and [latex]c[/latex] ,

if [latex]a=b[/latex] then [latex]a+b=b+c[/latex]

- For any numbers [latex]a[/latex] , [latex]b[/latex] , and [latex]c[/latex] ,
**Solve an equation using the Addition Property of Equality.**- Use the Addition Property of Equality to isolate the variable.
- Simplify the expressions on both sides of the equation.
- Check the solution.

## Glossary

**solution of an equation**- A solution to an equation is a value of a variable that makes a true statement when substituted into the equation. The process of finding the solution to an equation is called solving the equation.