Question: In algebra, what is a formula, and what does it describe about the variables it contains?

Sample answer: A formula is a mathematical equation that describes the relationship among two or more variables. It expresses a general rule connecting the variables, so once all but one of the values are known, the remaining variable can be found by substitution.

Key points:

• A formula is a mathematical equation.
• It describes the relationship among two or more variables.
• It states a general rule, not a single problem to solve.
• Knowing all but one variable lets you find the remaining one.

Rubric: Full credit: states that a formula is an equation and that it describes the relationship among two or more variables. Partial credit: identifies it as an equation or mentions variables but not the relationship. No credit: unrelated or incorrect definition.