Chapter 8.4, Problem 42E

To determine

To solve:

The given equation. Check your solution.

Answer to Problem 42E

The solution of our given equation would be $x=24$ .

Explanation of Solution

Given:

An equation: $x-3=21$ .

Calculation:

To solve our given equation, we use opposite operations as shown below:

  $\begin{array}{l}x-3=21\left(\text{Given equation}\right)\\ x-3+3=21+3\left(\text{Adding 3 on both sides}\right)\\ x=24\end{array}$

Let us verify our answer by substituting $x=24$ in our original equation.

  $\begin{array}{l}x-3=21\left(\text{Given equation}\right)\\ 24-3=21\left(\text{Substituting }x=24\right)\\ 21=21\end{array}$

Since both sides of equation are equal, therefore, $x=24$ is a solution of our given equation.