Предмет: Алгебра, автор: 04sribna04

Обчислити суму двадцяти перших елементів арифметичної прогресії, якщо а1=14 а10=-22

Ответы

Автор ответа: Mis45544

0

Ответ:a10=a1+9d=14+9d=-22

9d=-36

d=-4

a20=14+19×(-4)=14+(-76)=-62

S20=(14+(-62))×20/2=-480

Объяснение:

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