Question

Write a phrase as a variable expression: the difference of –15 and a number x.

Short answer

The variable expression for the given phrase is $-15-x$.

Step-by-step solution

Step-1 – Concept of variable expression

A variable expression or algebraic expression consists of one or more terms including variables and numbers that are connected by algebraic operations $+,-,\times ,÷$.

Step-2 – Consider the number

Let the unknown number be x.

So, we need to find the difference of the number –15 and the number x.

Step-3 – Write Variable expression

The term difference refers to subtraction. So, in order to find the difference of –15 and a number x, subtract the number x from the number –15 as shown below,

$\begin{array}{c}\text{Differenceof}-15\text{andanumber}x=\text{Differenceof}-15\text{and}x\\ =-15-x\end{array}$

Thus, the variable expression for the given phrase is $-15-x$.