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How Do You Evaluate an Algebraic Expression?

Note:

Plugging variables into an expression is essential for solving many algebra problems. See how to plug in variable values by watching this tutorial.

Keywords:

  • plug in
  • plugging in
  • substitution
  • problem
  • expression
  • variable
  • variables
  • substitute

Background Tutorials

  • Numerical and Algebraic Expressions

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        What is a Variable?

      What is a Variable?

      You can't do algebra without working with variables, but variables can be confusing. If you've ever wondered what variables are, then this tutorial is for you!

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        What Are Numerical and Algebraic Expressions?

      What Are Numerical and Algebraic Expressions?

      An expression is just a mathematical phrase. In this tutorial, you'll learn about two popular types of expressions: numerical and algebraic expressions. A numerical expression contains numbers and operations. An algebraic expression is almost exactly the same except it also contains variables. Check out this tutorial to learn about these two popular kinds of expressions!

  • Properties of Equality

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        What is the Substitution Property of Equality?

      What is the Substitution Property of Equality?

      If you ever plug a value in for a variable into an expression or equation, you're using the Substitution Property of Equality. This property allows you to substitute quantities for each other into an expression as long as those quantities are equal. Watch this tutorial to learn about this useful property!

Further Exploration

  • Introduction to Algebraic Expressions

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        How Do You Evaluate an Algebraic Expression by Plugging In Values?

      How Do You Evaluate an Algebraic Expression by Plugging In Values?

      Sometimes you have an algebraic expression with variables, and you know the values of those variables exactly, and you just need to plug in those values and get the value of the expression. Well, if that's what you have to do, then you've come to the right place, because this tutorial will show you exactly how to do it!

  • Solving For a Variable

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        How Do You Use the Solution from an Equation to Evaluate an Expression?

      How Do You Use the Solution from an Equation to Evaluate an Expression?

      If 3x=21, what is 9x? To get the answer, solve the equation for the variable. Then plug that variable value into the expression and simplify to get the answer. Follow this same process anytime you need to use an equation to evaluate an expression. Watch this tutorial to see this process in action!