When did barack obama become president of the united states?

Which technological breakthrough of the 1950s revolutionized the way that americans kept up with news and world events? a) radio b) internet c) television d) motion pictures

Which groups of people most directly benefited from song innovations in the song dynasty‘s open border policy?

How many soultions does the system of equations have y= -6x + 330x + 5y = 15a.one b.twoc.infinity manyd.none