Объяснение:
4)
Уравнение окружности (x – х₀)²+ (y – у₀)² = R² , (х₀ ; у₀)-координаты центра.В(3;-2)-центр, А(-1;-4) принадлежит окружности. Найдем R.
R²=АВ²= (3+1)²+(-2+4)² =4²+2²=20.
(x – 3)²+ (y +2)² =20.
5)
MN-диаметр , M(-2;1) , N(4;-5). Пусть О-середина MN , найдем координаты О.
х(О)= ( х(M)+х(N) )/2 у(О)= ( у(M)+у(N) )/2
х(О)= ( -2+4 )/2 у(О)= ( 1-5 )/2
х(О)= 11 у(О)= -2
О( 1 ;-2) .
R²=ОN²= (4+1)²+(-5+2)² =25+9=34.
(x – 1 )²+ (y +2)² =34.
There we met many children. We did not notice that they did not understand us. We were friends and played together. My family and I often walked along the streets. It was wonderful. Streets in Spain are very clean. We also visited a large aquarium. There we saw different fishes, sharks, and rays. We spent two weeks in Spain.
When we came back to Russia it was already snowing here. I enjoyed the trip.