Question

achar as raizes das equação X²-X-20=0

Answer 1

x² - x - 20 = 0

Δ = b² - 4ac
Δ= (-1)² - 4 . 1 . ( -20 )
Δ = 1 + 80
Δ = 81

x = (-b +- V81)/2 . 1
x =  - (-1) +- 9 / 2

x¹ = (1 + 9) / 2
x¹ = 5

x² = ( 1 - 9 ) / 2
x² = -4

V = { 5 , - 4 }

Answer 2

x² - x - 20 = 0
Fatorando:
(x - 5)(x + 4) = 0

x - 5 = 0 ---> x' = 5
x + 4 = 0 ---> x'' = - 4

S = { - 4 ; 5}