Math Problem Statement

If 2 ln(2) - ln(x + 2) = 1, then x = ?

Solution

Let's solve the given equation step by step:

The problem is:

2ln(2)ln(x+2)=12 \ln(2) - \ln(x + 2) = 1

We need to solve for xx.

Step 1: Simplify the equation

We start by moving ln(x+2)\ln(x + 2) to the other side:

2ln(2)=1+ln(x+2)2 \ln(2) = 1 + \ln(x + 2)

Now subtract 1 from both sides:

2ln(2)1=ln(x+2)2 \ln(2) - 1 = \ln(x + 2)

Step 2: Use properties of logarithms

We know that:

2ln(2)=ln(22)=ln(4)2 \ln(2) = \ln(2^2) = \ln(4)

Substitute that into the equation:

ln(4)1=ln(x+2)\ln(4) - 1 = \ln(x + 2)

Now express 11 as a logarithm. Since ln(e)=1\ln(e) = 1, we can write it as:

ln(4)ln(e)=ln(x+2)\ln(4) - \ln(e) = \ln(x + 2)

Step 3: Apply logarithm rules

Using the property ln(a)ln(b)=ln(ab)\ln(a) - \ln(b) = \ln\left(\frac{a}{b}\right), we get:

ln(4e)=ln(x+2)\ln\left(\frac{4}{e}\right) = \ln(x + 2)

Since the logarithms are equal, we can equate the arguments:

x+2=4ex + 2 = \frac{4}{e}

Step 4: Solve for xx

Now solve for xx:

x=4e2x = \frac{4}{e} - 2

Step 5: Simplify the expression

To simplify x=4e2x = \frac{4}{e} - 2, we get a common denominator:

x=42eex = \frac{4 - 2e}{e}

Thus, the value of xx is:

x=42eex = \frac{4 - 2e}{e}

Final Answer:

This matches option (D):

42ee\boxed{ \frac{4 - 2e}{e} }

Let me know if you'd like further details!


Here are 5 questions related to this problem:

  1. What are the key properties of logarithms used in this solution?
  2. How do you express a constant as a logarithmic expression?
  3. Why can we equate the arguments of logarithms once their forms match?
  4. How can the equation 2ln(2)2 \ln(2) be simplified using logarithmic rules?
  5. What does the base of the natural logarithm, ee, represent?

Tip: When solving logarithmic equations, always look to simplify by using properties like combining logarithms or exponentiation.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Logarithms
Algebra

Formulas

Properties of logarithms: ln(a) - ln(b) = ln(a/b)
Natural logarithm: ln(e) = 1

Theorems

Properties of logarithms

Suitable Grade Level

Grades 10-12