Question

A soma das soluções reais de xX² + 2x – 8 = 1 é:

Answer 1

X² + 2x – 8 = 1

X² + 2x – 9 = 0

Δ= 2² - (4 x 1 x (-9)) = 4 - (-36) = 40

x' = $\frac{-2 + \sqrt{40}}{2}$=$\frac{-2 + 2\sqrt{10}}{2}=-1 + 1\sqrt{10}$

x''= $\frac{-2 - \sqrt{40}}{2}$=$\frac{-2- 2\sqrt{10}}{2}=-1 -1\sqrt{10}$

Soma: x'+x'' = $-1+1\sqrt{10} -1-1\sqrt{10} =-2$

Resposta: -2