Предмет: Математика, автор: Nika5011901

a+b+c=5.Чему равна сумма а в квадрате+b в квадрате+с в квадрате?

Ответы

Автор ответа: Юлька8294

Квадрат суммы любого числа слагаемых равен сумме их квадратов плюс сумма ВСЕВОЗМОЖНЫХ попарных произведений, что даёт: 25=2*5+х. Отсюда х=15. Если не ошибаюсь)

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