Chapter 6.3, Problem 38E

To determine

To find : The value of $x$ .

Answer to Problem 38E

The value of $x$ is $6$ .

Explanation of Solution

Given information:

Consider the expression $\frac{39}{x+7}=\frac{21}{7}$ .

Calculation :

Consider the expression $\frac{39}{x+7}=\frac{21}{7}$ , where the value of $x$ is to be found.

Therefore,

  $\begin{array}{l}\frac{39}{x+7}=\frac{21}{7}\left[\text{use cross multiplication property}\right]\\ 39\times 7=21\times \left(x+7\right)\\ 273=21x+147\left[\text{move like terms at one side}\right]\\ 21x=273-147\\ 21x=126\\ x=\frac{126}{21}\left[\text{Divide}\right]\\ x=6\end{array}$

Therefore the value of $x$ is $6$ .