How can you solve $5^{x^2+8}=125^{2x}$ for x?

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Discussion Overview

The discussion revolves around solving the equation $5^{x^2+8}=125^{2x}$ for the variable x. Participants explore different approaches to the problem, including algebraic manipulation and verification of solutions.

Discussion Character

  • Mathematical reasoning
  • Homework-related
  • Exploratory

Main Points Raised

  • One participant rewrites $125^{2x}$ as $5^{6x}$, leading to the equation $x^2+8=6x$ and subsequently factors it to find $x=2$ and $x=4$.
  • Another participant confirms the solutions by substituting $x=2$ and $x=4$ back into the original equation, showing that both values satisfy the equation.
  • Some participants express a desire for more detailed steps in the solution process, indicating that they are more interested in the methodology than the final numerical answers.
  • There are comments about the use of calculators and checking answers with external tools like Wolfram Alpha, suggesting a cautious approach to relying solely on computational tools.
  • Several off-topic remarks about personal preferences and experiences related to living in Hawaii are included, which diverge from the mathematical focus of the thread.

Areas of Agreement / Disagreement

Participants generally agree on the correctness of the solutions found, but there is no consensus on the necessity of detailed steps or the use of calculators for verification.

Contextual Notes

Some participants mention a preference for checking answers with tools like Wolfram Alpha, indicating a potential limitation in their confidence in manual calculations. Additionally, there are informal discussions that detract from the mathematical focus.

Who May Find This Useful

Readers interested in algebraic problem-solving, verification methods, and those looking for community insights on mathematical reasoning may find this discussion useful.

karush
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$\tiny [6.3.74 Miliani HS$
Find x
$5^{x^2+8}=125^{2x}$
$\begin{array}{rlll}
\textsf{common base}&125^{2x}=(5^3)^{2x}=5^{6x}\\
\textsf{then } &x^2+8=6x\implies x^2-6x+8=0 \\
\textsf{factor}&(x-2)(x-4)=0\\
\textsf{get zeros}&x=2, \quad x=4\\
\end{array}$

should be ok
suggestions...
 
Mathematics news on Phys.org
that’s fine
 
I would suggest that you CHECK your answers!

If x= 2 then $x^2+ 8= 4+ 8= 12$ so $5^{x^2+ 8}= 5^{12}= 244140625$ while $125^{2x}= 125^{4}= 244140625$. Yes, they are equal!

If x= 4
then $x^2+ 8= 16+ 8= 24$ so $5^{x^2+ 8}= 5^{24}= 59604644775390625$ while $125^{2x}= 125^{8}= 59604644775390625$. Yes, they are equal!
 
If you live in Hawaii, how can you bear to do mathematics rather than being out on the beach every day?
 
there aways seems to be some non textbook trick with logs
 
Beer soaked ramblings follow.
Country Boy said:
If you live in Hawaii, how can you bear to do mathematics rather than being out on the beach every day?
Not everyone is fond of the sun and the beach.
Some would rather be indoors away from pesky flies and mosquitoes.
 
jonah said:
Beer soaked ramblings follow.

Not everyone is fond of the sun and the beach.
Some would rather be indoors away from pesky flies and mosquitoes.
im 76 and over weight I am embarrased to be seen in swimsuit
besides the mask restrictions have been ridiculus here. but they are getting ignored more and more finally,,
now they wondering if we will have condo colapse like florida :confused:
 
Country Boy said:
I would suggest that you CHECK your answers!

If x= 2 then $x^2+ 8= 4+ 8= 12$ so $5^{x^2+ 8}= 5^{12}= 244140625$ while $125^{2x}= 125^{4}= 244140625$. Yes, they are equal!

If x= 4
then $x^2+ 8= 16+ 8= 24$ so $5^{x^2+ 8}= 5^{24}= 59604644775390625$ while $125^{2x}= 125^{8}= 59604644775390625$. Yes, they are equal!
actually I am more interested in the steps
probably don't need the decimal unless there is some purpose for it
I ussually check with W|A if the book does not give answers
 
karush said:
actually I am more interested in the steps
probably don't need the decimal unless there is some purpose for it
I ussually check with W|A if the book does not give answers
Never trust the calculator!

-Dan
 

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