Question

АЛГЕБРА 7 КЛАСС ПОМОГИТЕ

Answer 1

Ответ 2
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Answer 2

$\dfrac{1}{4}\, c^2-\dfrac{4}{25}\, d^2=\Big(\dfrac{1}{2}\, c\Big)^2-\Big(\dfrac{2}{5}\, d\Big)^2=\Big(\dfrac{1}{2}\, c-\dfrac{2}{5}\, d\Big)\Big(\dfrac{1}{2}\, c +\dfrac{2}{5}\, d\Big)=\\\\\\=\Big(\dfrac{c}{2}-\dfrac{2d}{5}\Big)\Big(\dfrac{c}{2}+\dfrac{2d}{5}\Big)$