Solve Logarithm Equation 7^2x - 5*7^x - 24 =0

  • Context: Undergrad 
  • Thread starter Thread starter vt33
  • Start date Start date
  • Tags Tags
    Logarithm
Click For Summary

Discussion Overview

The discussion revolves around solving the logarithmic equation 7^2x - 5*7^x - 24 = 0. Participants explore different approaches to reformulate the equation, focusing on algebraic manipulation and substitution methods.

Discussion Character

  • Mathematical reasoning, Homework-related

Main Points Raised

  • One participant suggests starting with the equation 7^2x - 35^x - 24 = 0, although it is unclear if this is a correct transformation.
  • Another participant proposes letting y = 7^x, indicating this substitution could simplify the problem.
  • A third participant expresses confusion about the initial approach and seeks clarification on the connection to standard linear equations.
  • A later reply confirms the intention to solve the original equation by substituting y = 7^x, leading to the quadratic form y^2 - 5y - 24 = 0, which can be solved for y.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the best approach to solve the equation, and there are varying levels of understanding regarding the transformations and substitutions involved.

Contextual Notes

Some assumptions about the transformations may be missing, and the discussion does not resolve the correctness of the initial equation reformulation.

vt33
Messages
25
Reaction score
0
I need to solve 7^2x - 5*7^x - 24 =0. Am I on the right track by starting with 7^2x - 35^x - 24 = 0?
 
Mathematics news on Phys.org
Let [itex]y = 7^x[/itex] and see where that leads! :-)
 
?

I sorry, can elaborate. Are you talking about ax+by+c=0. If so, I'm still a little confused.
 
You did say "logarithm equation" in the title so I assumed you meant you want to solve this equation:

[tex]7^{2x} - 5 \times 7^x - 24 = 0[/tex]

If so then set [itex]y = 7^x[/itex] and since [itex]7^{2x} = \left(7^x\right)^2[/itex] your equation becomes

[tex]y^2 - 5y - 24 = 0[/tex]

which you can easily solve for y from which you can obtain x.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
7
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 55 ·
2
Replies
55
Views
8K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 8 ·
Replies
8
Views
1K