Question

Resolva a equação 2x²-x-1=0 ajuda aí galera :p

Answer 1

2x² - x - 1 = 0

a = 2
b = - 1
c = - 1

∆ = b² - 4ac
∆ = ( - 1 )² - 4 • 2 • ( - 1 )
∆ = 1 + 8
∆ = 9

x = - b ± √∆ / 2a
x = - ( - 1 ) ± √9 / 2 • 2
x = 1 ± 3 /4
x' = 1 + 3 /4 = 4/4 = 1
x" = 1 - 3 /4 = - 2/4 : 2 = - 1/2

S = { - 1/2, 1 }