Question

Quero que resolvam essa equação:
0,2n^2 + 1,8n - 126 = 0

Resolução completa !!!

Answer 1

Olá.

$\mathsf{0,2n^2 + 1,8n - 126 = 0}\\\\\\ \mathsf{\Delta=b^2-4ac}\\\mathsf{\Delta=1,8^2-4\cdot[0,2\cdot(-126)]}\\\mathsf{\Delta=3,24-4\cdot[-25,2]}\\\mathsf{\Delta=3,24+100,8}\\\mathsf{\Delta=104,04}\\\\\mathsf{\sqrt{\Delta}=\sqrt{104,04}=10,2}\\\\\\\mathsf{x=\dfrac{-b\pm\sqrt{\Delta}}{2a}=\dfrac{-1,8\pm10,2}{0,4}}\\\\\\\mathsf{x'=\dfrac{-1,8+10,2}{0,4}=\dfrac{8,4}{0,4}=\boxed{21}}\\\\\\\mathsf{x''=\dfrac{-1,8-10,2}{0,4}=\dfrac{-12}{0,4}}=\boxed{-30}\\\\\\\mathsf{S=\{\-30, 21\}}$

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