Questions: Fill in the missing values to make the equations true.
(a) log base 8 of 7 - log base 8 of 11 = log base 8 of square
(b) log base 3 of 8 + log base 3 of square = log base 3 of 88
(c) log base 8 of 25 = square log base 8 of 5
Transcript text: Fill in the missing values to make the equations true.
(a) $\log _{8} 7-\log _{8} 11=\log _{8} \square$
(b) $\log _{3} 8+\log _{3} \square=\log _{3} 88$
(c) $\log _{8} 25=$ $\square$ $] \log _{8} 5$
Solution
Solution Steps
Step 1: Solve part (a)
The equation given is:
\[
\log_{8} 7 - \log_{8} 11 = \log_{8} \square
\]
Using the logarithm subtraction rule \(\log_{a} b - \log_{a} c = \log_{a} \left(\frac{b}{c}\right)\), we can rewrite the left-hand side:
\[
\log_{8} 7 - \log_{8} 11 = \log_{8} \left(\frac{7}{11}\right)
\]
Thus, the missing value is \(\frac{7}{11}\).
Step 2: Solve part (b)
The equation given is:
\[
\log_{3} 8 + \log_{3} \square = \log_{3} 88
\]
Using the logarithm addition rule \(\log_{a} b + \log_{a} c = \log_{a} (b \cdot c)\), we can rewrite the left-hand side:
\[
\log_{3} 8 + \log_{3} \square = \log_{3} (8 \cdot \square)
\]
Set this equal to \(\log_{3} 88\):
\[
\log_{3} (8 \cdot \square) = \log_{3} 88
\]
Since the logarithms are equal, their arguments must be equal:
\[
8 \cdot \square = 88
\]
Solving for \(\square\):
\[
\square = \frac{88}{8} = 11
\]
Step 3: Solve part (c)
The equation given is:
\[
\log_{8} 25 = \square \cdot \log_{8} 5
\]
We know that \(25 = 5^2\), so:
\[
\log_{8} 25 = \log_{8} (5^2)
\]
Using the logarithm power rule \(\log_{a} (b^c) = c \cdot \log_{a} b\), we can rewrite the left-hand side:
\[
\log_{8} (5^2) = 2 \cdot \log_{8} 5
\]
Thus, the missing value is \(2\).