Solve Logarithm Math Problem: LOG3(X+3)+LOG3(X-1)=1

  • Thread starter Doubell
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    Logarithms
In summary, the conversation discusses a math problem involving logarithms, where the calculation is correct but the solution needs to be investigated further to determine the correct root. It is noted that logarithms are not defined for negative numbers, so the final solution would be the positive value of x. It is also mentioned that complex numbers and functions can define logarithms for negative numbers.
  • #1
Doubell
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Homework Statement


NEED HELP WITH THIS MATH PROBLEM: LOG3(X+3) + LOG3(X-1) = 1

Homework Equations


The Attempt at a Solution


I SAID LOG3(X+3) + LOG3 (X-1)
SIMPLIFIES TO LOG3(X+3)*(X-1) = 1
I.E LOG3(X^2 +2X - 3) = 1
THEN 3^1 = (X^2 +2X - 3)
AND 0 = (X^2 +2X - 6)
THEN USE THE QUADRATIC FORMULA TO FIND X AS {-2+/- 28^1/2}/2
JUST NEED A SECOND OPINION TO SEE IF ITS CORRECT.
 
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  • #2
The calculation is correct so far, but you have to investigate what root is solution of the original equation. Hint: is logarithm defined for negative numbers? ehild
 
  • #3
ehild said:
the calculation is correct so far, but you have to investigate what root is solution of the original equation. Hint: Is logarithm defined for negative numbers?


Ehild
ok so logarithms are not defined by negative values hence the root for the original equation would have to be the positive value of x which would have been {-2 +[28^1/2]}/2 is that the final solution.
 
  • #4
Correct for the real logarithmic function.

(Later you will learn about complex numbers and functions, and the complex logarithm is defined for negative numbers, too. )

ehild
 

Related to Solve Logarithm Math Problem: LOG3(X+3)+LOG3(X-1)=1

1. What is a logarithm?

A logarithm is a mathematical function that represents the power to which a base number must be raised to produce a given number. In other words, it is the inverse of an exponential function.

2. How do you solve a logarithm math problem?

To solve a logarithm math problem, you need to use the properties of logarithms to simplify the equation and isolate the variable. This may involve combining logarithms, using the power rule, and converting logarithmic expressions to exponential form.

3. What are the properties of logarithms?

There are four main properties of logarithms: the product property, the quotient property, the power property, and the inverse property. These properties allow us to manipulate logarithms and simplify equations.

4. How do you apply the properties of logarithms to solve the equation LOG3(X+3)+LOG3(X-1)=1?

First, use the product property to combine the two logarithms into one: LOG3((X+3)(X-1))=1. Then, use the power property to rewrite the equation as (X+3)(X-1)=3. Finally, solve for X by factoring the left side and using the quadratic formula.

5. What is the solution to the equation LOG3(X+3)+LOG3(X-1)=1?

The solution to this equation is X=2 or X=-4. These values can be verified by plugging them back into the original equation and simplifying.

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