Ken Darby, 82, a three-time Academy Award-winning composer who was credited with writing the Elvis Presley hit "Love Me Tender," died Friday in Los Angeles of heart failure. He won Oscars for best musical score in 1956 for the "King and I," which he co-adapted with Andre Previn. As musical director for the 1956 movie "Love Me Tender." he scored the film and wrote the title song, according to a Billboard music reference book. But official credit for the song was given to Mr. Darby's wife, Vera Watson, and Presley.