Вправи 401 - 467 » 416
416. Обчисліть ab/(〖4a〗^2- 〖3b〗^2 ), якщо a–1b = 5. b/a = 5, b = 5a. (a •5a)/(〖4a〗^2- 3 • 〖(5a)〗^2 ) = 〖5a〗^2/(〖4a〗^2- 3 • 〖25a〗^2 ) = 〖5a〗^2/(〖4a〗^2- 〖75a〗^2 ) = 〖5a〗^2/〖-71a〗^2 = –5/71.
416. Обчисліть ab/(〖4a〗^2- 〖3b〗^2 ), якщо a–1b = 5. b/a = 5, b = 5a. (a •5a)/(〖4a〗^2- 3 • 〖(5a)〗^2 ) = 〖5a〗^2/(〖4a〗^2- 3 • 〖25a〗^2 ) = 〖5a〗^2/(〖4a〗^2- 〖75a〗^2 ) = 〖5a〗^2/〖-71a〗^2 = –5/71.