Question

$1 - (4 \sqrt{5} - 9)(4 \sqrt{5 } + 9)$
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Answer 1

$1-(4\sqrt{5}-9)(4\sqrt{5}+9)=1-[(4\sqrt{5})^{2}-9^{2}]=1-80+81=\boxed2$

Answer 2

Ответ: 2
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