Пошаговое объяснение:
Пусть собств. скорость / км/ч/, тогда по течению скорость составила х+9, а против течения х-9
24/(х+9)=24/(х-9)=5
общий знаменатель (х+9)*(х-9) х не равен плюс или минус девяти. Приведем дроби к общему знаменателю. 24*(х+9+х-9)=5(х²-81), раскроем скобки, соберем все с одной стороны, приведем подобные и выйдем на квадратное уравнение.
5х²- 48х- 405=0, х₁,₂=(24±√(576+405*5))/5=(24±√2601)/5
(24±51)/5; х₁=15, х₂<0, не имеет смысла. Значит, собственная скорость лодки равна 15 км/час
ответ 15 км/ч
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Hugh Jackman was born October 12, 1968, in Sydney (Australia). He was the youngest of five children. After school, Hugh tried to quickly start an independent life, he studyed radio journalism at the University of Technology Sydney, and in spare time played in the theater. Then entered the Western Australian Academy of the Arts, to become a professional actor. When him grandmother died, she left him 3.5 thousand dollars - so much worth studying in the Academy. During his study, he was invited to one of the roles in the popular TV series "Neighbours", but Hugh refused, he didn't wanted to miss a lecture.
After Hugh got the lead role in the TV series "Corelli". He played in the musicals "Beauty and the Beast," "Sunset Boulevard," "Oklahoma!"
He is a very athletic man, he usually playing golf, rugby, cricket and even swimming.
отсюда понабери)
2)52000-6760=45240