Question:medium

If 5 - log10 root 1 + x + 4 log10 root 1-x = log10 1/ 1-x2, then 100 x equals

Updated On: Jan 15, 2026
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Correct Answer: 99

Solution and Explanation

The provided logarithmic equation is:

\[ 5 - \log_{10} \left( \sqrt{1+x} + 4 \log_{10} \sqrt{1-x} \right) = \log_{10} \frac{1}{\sqrt{1-x^2}} \]

This equation is simplified through a series of steps.

Step 1: Rewriting the Equation

The initial equation is rewritten as:

\[ 5 - \log_{10} \left( \sqrt{1+x} + 4 \log_{10} \sqrt{1-x} \right) = \log_{10} \left( \frac{1}{\sqrt{1-x^2}} \cdot \frac{1}{\sqrt{1-x}} \right) \]

Further simplification involves factoring and solving.

Step 2: Applying Logarithmic Properties

The left-hand side of the equation is simplified using logarithmic properties:

\[ 5 \log_{10} \left( \sqrt{1+x} + 4 \log_{10} \sqrt{1-x} \right) = \log_{10} \sqrt{1-x} = -\log_{10} \sqrt{1-x} \cdot \log_{10} \sqrt{1+x} \]

Step 3: Further Simplification

Logarithmic rules are applied to combine terms:

\[ 4 \log_{10} \left( \sqrt{1-x} \right) + \log_{10} \left( \sqrt{1-x} \right) = -5 \]

This simplifies to:

\[ \log_{10} \left( \sqrt{1-x} \right) = -1 \]

Step 4: Solving for \( x \)

The equation is solved for \( x \):

\[ \sqrt{1-x} = \frac{1}{10} \]

Squaring both sides eliminates the square root:

\[ 1 - x = \frac{1}{100} \]

Solving for \( x \) yields:

\[ x = 1 - \frac{1}{100} = \frac{99}{100} \]

Conclusion

The value of \( x \) is \( \frac{99}{100} \), and the solution is 99/100.

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