Предмет: Алгебра, автор: Аноним

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Автор ответа: LuciferMotningstar
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a=-1\\\\a(a+1)-(a-3)^2 = a^2+a-(a^2-6a+9)=\\=a^2+a-a^2+6a-9=7a-9=7*(-1)-9=\\=-16\\\\Otvet: -16.\\\\\boxed {(a-b)^2=a^2-2ab+b^2}

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