Question

Alguém pode responder pra me por favoor?

Answer 1

${x}^{2} - 20x - 99 = 0 \\ x = \frac{ - ( - 20) + - \sqrt{( - 20)^{2} - 4 \times 1 \times ( - 99)} }{2 \times 1} \\ x = \frac{20 + - \sqrt{400 -396 } }{2} \\ x = \frac{20 + - \sqrt{4} }{2} \\ x1 = \frac{20 + 2}{2} = \frac{22}{2} = 11 \\ x2 = \frac{20 - 2}{2} = \frac{18}{2} = 6$