Chapter 1, Problem 4CR

To determine

To define: a variable expression.

Explanation of Solution

Given information: Consider the question given to describe a variable expression.

A variable expression is a combination of numbers, operations or variables. Some examples of variable expression are $5a+3b$ , $m÷\frac{4}{3}$ , $-\frac{5}{2}x+1$ .

To evaluate a variable expression, we have to substitute a number for each variable and then we have to evaluate the resulting numerical expression.

For example, evaluate the expression $xy$ when $x=6$ and $y=2$ .

  $\begin{array}{l}xy\\ =6\times 2\text{ Substitute }6\text{ for }x\text{ and }2\text{ for }y.\\ =12\text{ Multiply}\text{.}\end{array}$