Question

Alguém me ajuda? Matemática

Answer 1

Resposta:

$1)~~(2x+5)^2=\\ \\ (2x)^2+2(2x)(5)+5^2=\\ \\ 4x^2+20x+25$

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$2)~~(a-6b)^2=\\ \\ a^2-2.(a)(6b)+(6b)^2=\\ \\ a^2-12ab+36b^2$

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$3)~~(3y-4).(3y+4)=\\ \\ (3y)^2-(4)^2=\\ \\ 9y^2-16$