Problem:
Find all real solutions to $\frac{\log (x+21)}{\log (5)}+\frac{\log (-13 x-16)}{\log (5)}=\frac{\log (-3 x-14)}{\log (5)}$
Answer:
$\left\{\left\{x\to \frac{1}{13} \left(-143-3 \sqrt{1807}\right)\right\},\left\{x\to \frac{1}{13} \left(-143+3 \sqrt{1807}\right)\right\}\right\}$
{'source': 'AMPS', 'file': 'amps/mathematica/algebra/log_equations/41541.txt'}