Question

Resolva a equação:
x² - x -20 = 0
(CALCULOS PFV)

Answer 1

a = 1
b = -1
c = -20
Δ = (b)² - 4ac
Δ = (-1)² - 4.1.(-20)
Δ = 1 + 80
Δ = 81

x = $x = \frac{- (-1) +- \sqrt{81}}{2.1}$
x = $x = \frac{1 +- 9}{2}$
$x' = \frac{1+9}{2} = \frac{10}{2} = 5$
$x'' = \frac{1-9}{2} = \frac{-8}{2} = -4$

S = {5, -4}