Question

resolver a equação x²-2x-2=0

Answer 1

Δ = b² - 4 · a · c
Δ = (-2)² - 4 ·1·(-2)
Δ = 4 + 8
Δ = 12

 $x_1,x_2 = \dfrac{-b\pm \sqrt{b^2-4ac}}{2a}\\\\ x_1 = \dfrac{-(-2) + \sqrt{12} }{2 \cdot 1} = \dfrac{\not2 \;+ \not2 \sqrt{3} }{\not2} = 1 + \sqrt{3} \\\\ x_2 = \dfrac{-(-2) - \sqrt{12} }{2 \cdot 1} = \dfrac{\not2 \;- \not2 \sqrt{3} }{\not2} = 1 - \sqrt{3}$