Problem 56 - Algebra 2

Question

Solve each equation. $$ \ln (2 x-1)=0 $$

Step-by-Step Solution

Answer

The solution to the equation \(\ln (2 x-1)=0\) is \(x = 1\).

Step 1: Understand the Properties of Logarithm

The natural logarithm of a number equals to 0 only when that number equals to 1. This comes from the definition of logarithm itself. Hence, for the given equation \(\ln(2x - 1) = 0\), we can deduce that \(2x - 1 = 1\).

Step 2: Solve for x

Now, the equation has been simplified to \(2x - 1 = 1\). Solve this for x. Add 1 to both sides of the equation to isolate the term with x, getting \(2x = 2\). Divide both sides by 2 to get \(x = 1\).

Key Concepts

Properties of Logarithms

The properties of logarithms are essential tools in mathematics. They allow us to simplify complex logarithmic expressions and solve equations. The natural logarithm, represented as \( \ln \), is the logarithm with base \( e \), where \( e \approx 2.718 \). One crucial property of logarithms is that \( \log_b (1) = 0 \) for any base \( b \), because any number raised to the power of 0 is 1. Hence, when we encounter \( \ln(a) = 0 \), it implies \( a = 1 \). This property helps us solve logarithmic equations efficiently. By identifying that \( \ln(2x - 1) = 0 \) suggests \( 2x - 1 = 1 \), we can progress without directly calculating powers of \( e \). Utilizing these properties correctly streamlines solving and understanding logarithmic equations.

Solving Logarithmic Equations

Solving logarithmic equations involves stepping through a series of logical deductions based on logarithmic properties. These equations often involve finding a value of a variable that satisfies a logarithmic equation like \( \ln(2x - 1) = 0 \). The first step usually involves applying the basic property: if \( \ln(a) = 0 \), then \( a = 1 \). This reduces the complexity of the problem.
To solve our example, start by setting the expression inside the logarithm equal to 1: \( 2x - 1 = 1 \). This step converts the logarithmic equation into a more approachable linear equation that we can solve through straightforward algebraic manipulation. By understanding these processes, you can confidently solve similar equations, making sense of how logarithmic and linear transformations work hand in hand.

Algebraic Manipulation

Algebraic manipulation is a cornerstone process in solving equations, especially after simplifying via properties of logarithms. Starting with \( 2x - 1 = 1 \), we aim to isolate \( x \) on one side of the equation. Begin by adding 1 to both sides: \( 2x = 2 \). This operation simplifies the equation, removing any constants on one side.
Next, divide both sides by 2, resulting in \( x = 1 \). It's crucial during every step to maintain equation balance, ensuring what we do to one side is done to the other. These basic yet powerful operations highlight how algebraic techniques transform simplified logarithmic equations into solvable forms. Each step, though simple, drives us toward a clear and correct solution.