## 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 so, the number is a solution.

If not, the number is not a solution.

**Properties of Equality**

Subtraction Property of Equality | Addition Property of Equality |

For any numbers \(a\), \(b\), and \(c\), \(\text{If } a = b\) | For any numbers \(a\), \(b\), and \(c\), \(\text{If } a = b\) |

Division of Property of Equality | Multiplication Property of Equality |

For any numbers \(a\), \(b\), and \(c\ne 0\), \(\text{If } a = b\) | For any numbers \(a\), \(b\), and \(c\), \(\text{If } a = b\) |