Solve the following equation ln(x^2-8x+13)=0

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In summary, the conversation discusses solving the equation ln(x2-8x+13)=0, with the suggestion to use the rule ln(ab)=ln(a)+ln(b) and the reminder to only take the log of a positive number. The solution is found to be x2/8x=e-ln13.
  • #1
A_Munk3y
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Homework Statement


Solve the following equation:
ln(x2-8x+13)=0



The Attempt at a Solution


not much luck with this one. i just learned this stuff and I am having problems with it'
Anyways, i got
ln(x2-8x+13=0
=>lnx2-ln8x+ln13=0
=>lnx2-ln8x=-ln13
=>ln(x2/8x)=-ln13
=>eln(x2/8x)=e-ln13
=>x2/8x=e-ln13

im just going to stop there cause i think I am going in the wrong direction
 
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  • #2
[tex]ln(a+b)\neq ln(a)+ln(b)[/tex]

But rather,

[tex]ln(ab)=ln(a)+ln(b)[/tex]

Firstly, take the exponential of both sides, since [tex]e^{ln(x)}=x[/tex]

But also remember that you can only take the log of a positive number, so you might need to discard a value when you solve for x.
 
  • #3
Oh, ok :)
I got it! Thank you
 
  • #4
No problem :smile:
 

1. What is the solution to the equation ln(x^2-8x+13)=0?

The solution to this equation is x = 3 or x = 5. This can be solved by taking the inverse natural logarithm of both sides, which cancels out the ln function and leaves you with x^2-8x+13=1. Then, you can use the quadratic formula to solve for x.

2. Is there any other way to solve this equation without using the quadratic formula?

Yes, there is another way to solve this equation by using the properties of logarithms. You can rewrite the equation as ln(x^2-8x+13)=ln(1), and then use the property that ln(a)=ln(b) if and only if a=b. This will give you x^2-8x+13=1, which can be solved using basic algebraic methods.

3. Can I use a calculator to solve this equation?

Yes, you can use a calculator to solve this equation. Most scientific calculators have a natural logarithm function (ln) and an inverse natural logarithm function (e^x), which can be used to solve equations involving logarithms.

4. Are there any restrictions on the values of x in this equation?

Yes, there are restrictions on the values of x in this equation. Since the natural logarithm function is only defined for positive numbers, the expression inside the ln function must be greater than 0. This means that x^2-8x+13>0, which leads to the solution set of x>3 and x<5.

5. Can I solve this equation if the exponent is not 2?

Yes, you can solve this equation if the exponent is not 2. The methods for solving equations with logarithms remain the same, regardless of the exponent. However, the resulting quadratic equation may be more complex and may require more advanced algebraic techniques to solve.

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