Пусть скорость течения реки - х.
11/(18+x)=7/(18-х)
198-11x=126+7x
18x=72
x=4
Ответ: скорость течения реки 4 км/ч.
This summer I spent with my grandmother. We had fun, and not only rested well and worked, helped my beloved grandmother. We went to the river, there were a lot of people and I met a company of boys. We still communicate despite the distance. When I arrived home to my parents, I saw that my parents decided to surprise me by putting a huge pool that was the best summer of my life
Ответ: 90<110<180, поэтому cos 110 отрицателен. Tg 190 роложителен. Произведение отрицательно.
Объяснение: