ответ: so, in my opinion there are a lot of animals, which can help people. for example, farmers use their horses to carry some products like milk or hay to a barn. also we can see cats and dogs, which amazingly cope with a person's stress and anxiety. pets can notice some dangerous illnesses, even the owner have never thought of this. if we talk about bees, they are really important too. the bees help people with doing a huge amount of honey, which increases hemoglobin and strengthens the immune system. everybody know snakes and a lot of people are afraid of them, but they also help people a lot. snake venom is used to make medicines and it saves people's lives. so, animals are not only good friends and companions, but also they are really important and useful.
Объяснение:
Кожний член арефметичної прогресії знаходиться по формулі
аn=a₁+d(n-1) отже:
a₆=a₁+5d
a₄=a₁+3d
a₅=a₁+4d
Підставимо отримані значення у систему:
З першого рівняння знаменник арефметичної прогресії:
8d=4
d=0,5
2а₁+7*0,5=12
2а₁=15,5
а₁=7,75