Question

Formula Resolutiva determine a raízes da equação x²- 7x-8=0​

Answer 1

Resposta:

Dados:⎩⎪⎪⎨⎪⎪⎧a=1b=−7c=−8

\begin{gathered}b^{2}-4.a.c\\\\-7^{2}-4.1.(-8)\\\\49-(-32)\\\\49+32\\\\\Delta=81\end{gathered}b2−4.a.c−72−4.1.(−8)49−(−32)49+32Δ=81

\begin{gathered}\frac{-b \frac{+}{-} \sqrt{81} }{2.1}\\\\\frac{-(-7) \frac{+}{-} 9}{2}\\\\x'= \frac{-(-7)+9}{2}=\frac{16}{2}=8\\\\x"= \frac{-(-7)-9}{2}= \frac{-2}{2}=-1\end{gathered}2.1−b−+812−(−7)−+9x′=2−(−7)+9=216=8x"=2−(−7)−9=2−2=−1