## Evaluating Variable Expressions with Integers

Now we can evaluate **expressions** that include multiplication and division with integers. Remember that to evaluate an expression, substitute the numbers in place of the variables, and then simplify.

## Example

\(\text{Evaluate}\phantom{\rule{0.2em}{0ex}}2{x}^{2}-3x+8\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}x=-4.\)

### Solution

Simplify exponents. | |

Multiply. | |

Subtract. | |

Add. |

Keep in mind that when we substitute \(-4\) for \(x,\) we use parentheses to show the multiplication. Without parentheses, it would look like \(2·{-4}^{2}-3·-4+8.\)

## Example

\(\text{Evaluate}\phantom{\rule{0.2em}{0ex}}3x+4y-6\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}x=-1\phantom{\rule{0.2em}{0ex}}\text{and}\phantom{\rule{0.2em}{0ex}}y=2.\)

### Solution

Substitute \(x=-1\) and \(y=2\). | |

Multiply. | |

Simplify. |