Math Problem Statement

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Solution

To solve the equation log(x13)+3log(2)=log(3x+1)\log(x - 13) + 3\log(2) = \log(3x + 1), we can follow these steps:

Step 1: Simplify the equation

We know from logarithmic properties that alog(b)=log(ba)a \log(b) = \log(b^a). So, we can rewrite 3log(2)3\log(2) as log(23)\log(2^3).

log(x13)+log(23)=log(3x+1)\log(x - 13) + \log(2^3) = \log(3x + 1)

Since 23=82^3 = 8, the equation becomes:

log(x13)+log(8)=log(3x+1)\log(x - 13) + \log(8) = \log(3x + 1)

Step 2: Combine the logarithms on the left-hand side

Using the logarithmic property log(a)+log(b)=log(a×b)\log(a) + \log(b) = \log(a \times b), we can combine the logarithms:

log((x13)×8)=log(3x+1)\log((x - 13) \times 8) = \log(3x + 1)

Simplify the left-hand side:

log(8x104)=log(3x+1)\log(8x - 104) = \log(3x + 1)

Step 3: Remove the logarithms

If log(a)=log(b)\log(a) = \log(b), then a=ba = b. Therefore, we can equate the arguments of the logarithms:

8x104=3x+18x - 104 = 3x + 1

Step 4: Solve the linear equation

Subtract 3x3x from both sides:

5x104=15x - 104 = 1

Add 104 to both sides:

5x=1055x = 105

Divide by 5:

x=21x = 21

Step 5: Check the solution

Substitute x=21x = 21 back into the original logarithmic expressions to ensure they are defined and valid:

  • x13=2113=8x - 13 = 21 - 13 = 8 (which is positive, so valid for logarithms).
  • 3x+1=3(21)+1=63+1=643x + 1 = 3(21) + 1 = 63 + 1 = 64 (also positive).

Since both arguments are positive, x=21x = 21 is a valid solution.

Final Answer:

The solution to the equation is x=21x = 21.

Would you like further details on any of these steps or have additional questions?


Here are 5 related questions that could expand your understanding:

  1. How do logarithmic properties help simplify equations?
  2. What happens if one side of the logarithmic equation is negative?
  3. How do you solve an equation involving logarithms with different bases?
  4. What is the significance of ensuring that logarithmic arguments are positive?
  5. Can you have a logarithmic equation where no solution exists?

Tip: Always check that the arguments of logarithmic functions remain positive when solving equations.

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Math Problem Analysis

Mathematical Concepts

Logarithms
Equations

Formulas

Logarithmic properties

Theorems

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Suitable Grade Level

Grades 10-12