How do scientists locate the epicenter of an earthquake?

Triangulation,

Explanation:

This can be understood with the occurrence of the earthquakes and the seismic waves as there are three waves as the P, waves which are the fastest and hence called as the primary waves and runs at a constant speed.  The surface waves have more variable speeds they tend to move along the tracks and they originate from the center of the earthquake and are thus daily monitored and help to determine the epicenter of the place. Thus the epicenter is directly found above the hypocenter of the focus at this point the earthquakes originate.

2. x2 + 8x + 12 = 0 to prove: x = -6 or x = -2