Converting the Logarithmic Equation to Exponential Form

Oct 13, 2025 by miodeya.com 34 views

Introduction

Logarithmic equations can be challenging to solve, but with the right approach, they can be broken down into manageable steps. In this article, we will focus on solving a specific logarithmic equation and provide a step-by-step guide on how to find the approximate value of the variable $x$ .

The Equation

The given equation is:

$\log _{\frac{3}{4}} 25 = 3x - 1$

Understanding Logarithms

Before we dive into solving the equation, let's quickly review the concept of logarithms. A logarithm is the inverse operation of exponentiation. In other words, if $a^b = c$ , then $\log_a c = b$ . The logarithm of a number to a certain base is the exponent to which the base must be raised to produce that number.

Converting the Logarithmic Equation to Exponential Form

To solve the equation, we need to convert it from logarithmic form to exponential form. We can do this by using the definition of logarithms:

$\log _{\frac{3}{4}} 25 = 3x - 1$

$(\frac{3}{4})^{3x - 1} = 25$

Simplifying the Equation

Now that we have the equation in exponential form, we can simplify it by raising both sides to the power of $\frac{1}{3x - 1}$ :

$25^{\frac{1}{3x - 1}} = (\frac{3}{4})^{3x - 1}$

Using the Change of Base Formula

To make the equation easier to solve, we can use the change of base formula to convert the logarithm to a common base, such as base 10:

$\log_{\frac{3}{4}} 25 = \frac{\log_{10} 25}{\log_{10} \frac{3}{4}}$

Substituting the Change of Base Formula into the Equation

Now that we have the change of base formula, we can substitute it into the equation:

$\frac{\log_{10} 25}{\log_{10} \frac{3}{4}} = 3x - 1$

Simplifying the Equation Further

To simplify the equation further, we can use a calculator to find the values of the logarithms:

$\frac{\log_{10} 25}{\log_{10} \frac{3}{4}} \approx \frac{1.39794}{-0.12494}$

$\frac{\log_{10} 25}{\log_{10} \frac{3}{4}} \approx -11.18$

Solving for $x$

Now that we have the simplified equation, we can solve for $x$ :

$-11.18 = 3x - 1$

$-10.18 = 3x$

$x \approx -3.3933$

Conclusion

In this article, we solved a logarithmic equation by converting it to exponential form, simplifying it, and using the change of base formula. We then used a calculator to find the values of the logarithms and solved for $x$ . The approximate value of $x$ is $-3.3933$ .

Answer

The correct answer is:

A. ${$ -3.396$}$

Discussion

This problem requires a good understanding of logarithms and their properties. The change of base formula is a useful tool for simplifying logarithmic equations. However, it's worth noting that the equation can be solved using other methods, such as using a calculator to find the value of the logarithm directly.

Additional Tips

When solving logarithmic equations, it's essential to understand the properties of logarithms and how to apply them.
The change of base formula can be a useful tool for simplifying logarithmic equations.
A calculator can be a valuable resource for finding the values of logarithms and solving equations.

References

[1] "Logarithms" by Math Is Fun
[2] "Change of Base Formula" by Math Is Fun
[3] "Solving Logarithmic Equations" by Khan Academy
Frequently Asked Questions: Solving Logarithmic Equations =====================================================

Q: What is the definition of a logarithm?

A: A logarithm is the inverse operation of exponentiation. In other words, if $a^b = c$ , then $\log_a c = b$ . The logarithm of a number to a certain base is the exponent to which the base must be raised to produce that number.

Q: How do I convert a logarithmic equation to exponential form?

A: To convert a logarithmic equation to exponential form, you can use the definition of logarithms. For example, if $\log_a b = c$ , then $a^c = b$ .

Q: What is the change of base formula?

A: The change of base formula is a formula that allows you to change the base of a logarithm. It is given by:

$\log_b a = \frac{\log_c a}{\log_c b}$

where $c$ is any positive real number not equal to 1.

Q: How do I use the change of base formula to simplify a logarithmic equation?

A: To use the change of base formula to simplify a logarithmic equation, you can substitute the formula into the equation and simplify. For example, if $\log_{\frac{3}{4}} 25 = 3x - 1$ , you can use the change of base formula to rewrite the equation as:

$\frac{\log_{10} 25}{\log_{10} \frac{3}{4}} = 3x - 1$

Q: What is the difference between a logarithmic equation and an exponential equation?

A: A logarithmic equation is an equation that involves a logarithm, while an exponential equation is an equation that involves an exponent. For example, the equation $\log_{\frac{3}{4}} 25 = 3x - 1$ is a logarithmic equation, while the equation $(\frac{3}{4})^{3x - 1} = 25$ is an exponential equation.

Q: How do I solve a logarithmic equation?

A: To solve a logarithmic equation, you can use the following steps:

Convert the logarithmic equation to exponential form.
Simplify the equation using the change of base formula.
Use a calculator to find the values of the logarithms.
Solve for the variable.

Q: What are some common mistakes to avoid when solving logarithmic equations?

A: Some common mistakes to avoid when solving logarithmic equations include:

Not converting the logarithmic equation to exponential form.
Not using the change of base formula to simplify the equation.
Not using a calculator to find the values of the logarithms.
Not solving for the variable.

Q: How do I check my answer when solving a logarithmic equation?

A: To check your answer when solving a logarithmic equation, you can plug the value of the variable back into the original equation and simplify. If the equation is true, then your answer is correct.

Q: What are some real-world applications of logarithmic equations?

A: Logarithmic equations have many real-world applications, including:

Modeling population growth and decay.
Analyzing financial data.
Studying the behavior of electrical circuits.
Solving problems in physics and engineering.

Q: How can I practice solving logarithmic equations?

A: You can practice solving logarithmic equations by working through problems in a textbook or online resource. You can also try solving logarithmic equations on your own using a calculator or online tool.