How Do You Solve Logarithmic Equations with Coefficients?

  • Thread starter darshanpatel
  • Start date
He knew he needed to exponentiate or take another log to get rid of the logarithms, but was struggling with the +1 on the left side. Another user suggested using the property 6^{1+a} = 6 \times 6^a, and Chetan was able to solve the equation and confirm that the solution, x=8, worked.
  • #1
darshanpatel
139
0

Homework Statement



Solve:

log6(2x-5)+1=log6(7x+10)

Homework Equations



-None-

The Attempt at a Solution



I know we will need to exponentiate both side by 6 to get rid of the log, or either take another log.

I need help with getting rid of the +1 on the left side of the = sign because that is what is baffling me.
 
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  • #2
Hint: [itex]6^{1+a} = 6 \times 6^a[/itex], doesn't it?
 
  • #3
log6(2x-5)+1=log6(7x+10)

6log6(2x-5)+1=6log6(7x+10)

6(2x-5)=7x+10

12x-30=7x+10

5x=40

x=8

I checked it and it worked, thanks for the help man!
 
  • #4
darshanpatel said:

Homework Statement



Solve:

log6(2x-5)+1=log6(7x+10)

Homework Equations



-None-

The Attempt at a Solution



I know we will need to exponentiate both side by 6 to get rid of the log, or either take another log.


I need help with getting rid of the +1 on the left side of the = sign because that is what is baffling me.

log66 = ?

Chet
 

Related to How Do You Solve Logarithmic Equations with Coefficients?

1. What is a logarithm?

A logarithm is an inverse function of an exponent. It helps us solve for x when it appears in an exponential equation.

2. How do I use logs to solve for x?

To use logs to solve for x, you need to first take the logarithm of both sides of the equation. Then, use algebraic manipulation and properties of logarithms to isolate and solve for x.

3. Can I use any base for logarithms?

Yes, you can use any base for logarithms. However, the most commonly used bases are 10, e (Euler's number), and 2.

4. What are the common mistakes when using logs to solve for x?

The most common mistakes when using logs to solve for x include forgetting to take the logarithm of both sides of the equation, not applying the correct properties of logarithms, and not checking for extraneous solutions.

5. Are there any tips for using logs to solve for x?

Some tips for using logs to solve for x include practicing basic algebraic manipulation, familiarizing yourself with the properties of logarithms, and checking your solutions for extraneous values.

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