### Video Transcript

What is the variable in the expression six 𝑥 plus 80?

In this question, we’re given a linear expression six 𝑥 plus 80, and we’re asked to determine what is the variable in this expression. So we should start by recalling what we mean by a variable. And there’s many different definitions of a variable, and they can go quite in depth. So instead, we’ll just look at the main property of a variable. It’s a value which does not remain constant.

For example, we can see that 80 is not a variable. It remains constant; it’s always equal to 80. Similarly, six remains constant; it’s always equal to six. However, our value of 𝑥 can vary; it can take on any number of values.

Therefore, we can say in the expression six 𝑥 plus 80, 𝑥 is the variable.