Answered

Select the correct answer.

What is the value of [tex]$x$[/tex] in [tex]$2\left(5^x\right)=14$[/tex]?

A. [tex][tex]$\frac{\log 7}{\log 5}$[/tex][/tex]
B. [tex]$\frac{\log 5}{\log 7}$[/tex]
C. [tex]$\log 2$[/tex]
D. [tex]$\log 7 - \log 5$[/tex]



Answer :

To find the value of [tex]\( x \)[/tex] in the equation [tex]\( 2 \left(5^x\right) = 14 \)[/tex], follow the steps below:

1. Isolate the Exponential Term:
First, divide both sides of the equation by 2 to isolate the exponential term:
[tex]\[ 5^x = \frac{14}{2} \][/tex]
Simplifying the right-hand side, we get:
[tex]\[ 5^x = 7 \][/tex]

2. Apply the Logarithm:
To solve for [tex]\( x \)[/tex], take the logarithm of both sides. While any logarithm base can be used, the common logarithm (base 10) or the natural logarithm (base [tex]\( e \)[/tex]) are typically used. We'll use the common logarithm (base 10):
[tex]\[ \log(5^x) = \log(7) \][/tex]

3. Use the Power Rule of Logarithms:
Use the logarithmic identity that states [tex]\( \log(a^b) = b \log(a) \)[/tex]:
[tex]\[ x \log(5) = \log(7) \][/tex]

4. Solve for [tex]\( x \)[/tex]:
Isolate [tex]\( x \)[/tex] by dividing both sides of the equation by [tex]\( \log(5) \)[/tex]:
[tex]\[ x = \frac{\log(7)}{\log(5)} \][/tex]

Therefore, the correct value for [tex]\( x \)[/tex] is:
[tex]\[ \boxed{\frac{\log 7}{\log 5}} \][/tex]

Hence, the correct answer is:
A. [tex]\(\frac{\log 7}{\log 5}\)[/tex]