Answer
The solution set is $\{28\}$.
Work Step by Step
The given equation is
$2\log x - \log 7 = \log 112$
Use power rule.
$\log x^2 - \log 7 = \log 112$
Use quotient rule.
$\log \left ( \frac{x^2}{7} \right ) = \log 112$
$\frac{x^2}{7} = 112$
Multiply both sides by $7$.
$7\cdot \frac{x^2}{7} = 7\cdot 112$
Simplify.
$x^2 = 784$
$x^2 = 28^2$
Take the square root of both sides.
$x=28$.
