A coefficient is a number that is multiplied by a variable.

• In the expression  , the coefficient of  is 3.
• In the expression  , the coefficient of  is 1, because  .

In an expression like , the number 2 is called the constant term. It doesn’t change when the variable changes.

• In the expression , the constant term is 9.
• In the expression , the constant term is -8.
• In the expression , the constant term is 12.

To expand an expression, use the distributive property to rewrite a product as a sum. The new expression is equivalent to the original expression.

For example, the expression can be expanded to get the equivalent expression .

To factor an expression, use the distributive property to rewrite a sum as a product. The new expression is equivalent to the original expression.

For example, the expression can be factored to get the equivalent expression .

Terms are the parts of an expression that are added together. They can be a single number, a variable, or a number and a variable that are multiplied together.

• 7, , and  are examples of terms.
• The expression has 3 terms: , 3, and -18.