How to Solve Logarithmic Equations with Different Bases?

  • Thread starter emma3001
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    Logarithms
In summary, the conversation is about solving the equation log2x + log4x = 5. The suggested method is to convert the logs to the same base using the formula log_a(x) = log_b(x)/log_b(a). The person asking for help is advised to post the problem on a forum to receive further assistance.
  • #1
emma3001
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Solve the equation log2x + log4x= 5. To start, should I change this to an exponential... I am stuck because I have only done log questions that have the same base.
 
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  • #2
Convert them to the same base log_a(x)=log_b(x)/log_b(a).
 
  • #3
emma3001 said:
Solve the equation log2x + log4x= 5. To start, should I change this to an exponential... I am stuck because I have only done log questions that have the same base.
What do you mean by "log2x+ log4x= 5"? I would interpret that as log(2x)+ log(4x)= 5 so log(6x)= 5 which is easy. If you mean "log_2(x)+ log_4(x)= 5" then use Dick's hint.
log_4(x)= log_2(x)/log_2(4)= ?
 
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  • #4
Dick said:
Convert them to the same base log_a(x)=log_b(x)/log_b(a).

can u help solving a problem?
 
  • #5
can u help solve a problem?
 
  • #6
Can u post the problem? Under Forum Tools, "Post a New Thread". That's your first step.
 

1. What is a logarithm?

A logarithm is the inverse of an exponential function. It is used to solve equations where the variable is in the exponent.

2. How do you solve for x in a logarithmic equation?

To solve for x in a logarithmic equation, you can use the properties of logarithms to rewrite the equation in a simpler form and then solve for x using algebraic techniques.

3. What are the properties of logarithms?

The three main properties of logarithms are the product rule, quotient rule, and power rule. These properties allow you to manipulate logarithmic equations and simplify them.

4. Can you explain the steps for solving a logarithmic equation?

To solve a logarithmic equation, follow these steps:
1. Use the properties of logarithms to rewrite the equation in a simpler form.
2. Isolate the logarithmic expression on one side of the equation.
3. Convert the logarithmic expression into an exponential expression.
4. Solve for the variable using algebraic techniques.
5. Check your answer by plugging it back into the original equation.

5. What are some real-life applications of logarithms?

Logarithms are used in a variety of fields, including finance, biology, and astronomy. They are useful for modeling exponential growth and decay, measuring the intensity of earthquakes and sound, and calculating pH levels in chemistry.

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