Solve the following loganthmic equation. \( \log (8 x+9)=1+\log (x-4) \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. (b). The solution set is \( \} \). (Simplify your answer. Type an exact answer. Use a comma to separate answers as needed. B. There is no solution.
Real Tutor Solution
Answer
Solution
Reviewed and approved by the UpStudy tutoring team
The Deep Dive
To solve the equation \( \log (8x + 9) = 1 + \log (x - 4) \), first, we can use the properties of logarithms to rewrite it. The right side can be transformed as \( \log (10) + \log (x - 4) = \log (10(x - 4)) \). This gives us: \( \log (8x + 9) = \log (10(x - 4)) \). By equating the arguments (since the logarithm is a one-to-one function), we have: \( 8x + 9 = 10(x - 4) \). Expanding and simplifying gives: \( 8x + 9 = 10x - 40 \) => \( 9 + 40 = 10x - 8x \) => \( 49 = 2x \) => \( x = \frac{49}{2} = 24.5 \). It's important to check if this solution falls within the valid domain of the logarithms. We need \( x - 4 > 0\) which implies \( x > 4\) — and since \( 24.5 > 4\), it's valid. Thus, the solution set is \( \{ 24.5 \} \). So the answer is: (b). The solution set is \( \{ 24.5 \} \).