Question

x² +8x =240 resolução...

Answer 1

$x^2+8x=240\\\\ x^2+8x-240=0\\\\ \Delta=b^2-4\cdot a\cdot c\\ \Delta=8^2-4\cdot1\cdot(-240)\\ \Delta=64+960\\ \Delta=1024\\\\ x=\dfrac{-b\pm\sqrt{\Delta}}{2a}=\dfrac{-8\pm\sqrt{1024}}{2\cdot1}=\dfrac{-8\pm32}{2}\Longrightarrow\begin{cases}x_1=-4+16=12\\x_2=-4-16=-20\end{cases}\\\\ S=\{-20,12\}$

Answer 2

A resposta da equação  é 36 e 28