Solve Log Equation: Find Value of x

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SUMMARY

The discussion focuses on solving the logarithmic equation log x - 1/2log(x-1/2) = log(x+1/2) - 1/2log(x+1/8). The user initially derived a cubic equation, 4x^3 - 8x^2 - 4x - 1 = 0, but was informed that the correct approach should yield a quadratic equation, specifically 3x^2 - 2x - 1 = 0. The correct solution to the equation is x = 1, as confirmed by the textbook answer.

PREREQUISITES
  • Understanding of logarithmic properties, specifically log a + log b = log(ab) and log a - log b = log(a/b).
  • Familiarity with solving polynomial equations, particularly cubic and quadratic forms.
  • Basic algebra skills to manipulate and simplify logarithmic expressions.
  • Knowledge of the quadratic formula for finding roots of quadratic equations.
NEXT STEPS
  • Review the properties of logarithms in detail, focusing on their application in equations.
  • Practice solving cubic and quadratic equations, emphasizing the transition between different polynomial forms.
  • Learn how to derive polynomial equations from logarithmic expressions step-by-step.
  • Explore the quadratic formula and its application in solving quadratic equations like 3x^2 - 2x - 1 = 0.
USEFUL FOR

Students studying algebra, particularly those focusing on logarithmic equations and polynomial solutions, as well as educators looking for examples of common mistakes in solving such equations.

kukki1990
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Homework Statement


Find the value of x


Homework Equations


log x - 1/2log(x-1/2) = log(x+1/2) - 1/2log(x+1/8)


The Attempt at a Solution


used the log a + log b = log a*b & log a - log b = loga/b

and got a cubic equation 4x^3-8x^2-4x-1 = 0

but the answer in the book is x=1
 
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Could you please show your steps on how you've obtained that polynomial?
 
You should be getting a quadratic (3x^2-2x-1=0) which will give you the correct answer. However, I can't tell you where you are going wrong until you show me your workings...
 

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