Short answers, pulled from the story.
Ronald Reagan won the 1980 presidential election with 489 Electoral College votes and 50.7% of the popular vote. Jimmy Carter received 49 Electoral College votes and 41.0% of the popular vote, a margin of nearly 10 percentage points in the popular vote.
Carter's defeat stemmed from a combination of stagflation, the prolonged Iran hostage crisis, and a failed military rescue attempt on the 25th of April 1980, that killed eight servicemen. Post-election research found the landslide was widely seen as a repudiation of Carter rather than an embrace of Reagan's conservatism.
The taking of 52 American hostages at the U.S. embassy in Tehran on the 4th of November 1979, initially boosted Carter's approval ratings into the sixty-percent range. As the crisis dragged through election day without resolution, and after a botched rescue attempt left eight servicemen dead in April 1980, it became a major liability for Carter and a symbol of American impotence.
John B. Anderson was an Illinois congressman who lost the Republican primaries to Reagan and then ran as an independent candidate in the general election. He won 6.6% of the popular vote and no Electoral College votes; his best state result was 15% in Massachusetts.
In the 28th of October 1980 debate in Cleveland, Ohio, Reagan responded to Carter's attacks on his record with the phrase "There you go again." In his closing remarks, he asked viewers whether they were better off than they had been four years earlier, a question that resonated strongly with a public struggling with inflation and unemployment.
Many historians regard the 1980 election as a political realignment. Republicans captured the Senate for the first time since 1954. Carter's loss was the worst by a sitting president since 1932, and the election signaled a new electoral power for the suburbs and the Sun Belt that would reshape party coalitions through the 1980s and 1990s.