Question

alguem sabe responder para mim esta equação
x²-x-20=0

Answer 1

$x^{2} -x - 20 = 0$

Resolvendo por Bháskara:

$x = \dfrac{-b \pm \sqrt{b^2 -4*a*c}}{2*a}$

a=1, b=−1, c=−20

Δ=b²−4ac
Δ=(−1)²−4*(1)*(−20)
Δ=1+80
Δ= 81

$x = \dfrac{-b \pm \sqrt{\triangle}}{2*a}$

$x = \dfrac{-(-1) \pm \sqrt{81}}{2*1} \\ \\ \\ x = \dfrac{1 \pm 9}{2} \\ \\ \\ x' = \dfrac{1 + 9}{2} \\ \\ \\ x' = \dfrac{10}{2} \\ \\ \\ x' = 5 \\ \\ \\ \\ x'' = \dfrac{1 - 9}}{2} \\ \\ \\ x'' = \dfrac{-8}}{2} \\ \\ \\ x'' = -4$


S = {5,  -4}