Предмет: Математика, автор: Nana2997

В арифметической прогрессии сумма третьего и седьмого членов равна 10, первый член равен -3. Найти разность прогрессии.

Ответы

Автор ответа: Кротилла

$n_3+n_7=10$
преобразуем
$n_1+2d+n_1+6d=10$ где d-разность АП
$2n_1+8d=10$
$2*(-3)+8d=10$
$8d=10-(-6)$
$8d=16$
$d= \frac{16}{8}$
$d=2$

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