Respostas

2014-05-22T17:47:51-03:00
X²-x-20=0
Δ= (-1)²-4.1.(-20)
Δ=1+80 = 81 √Δ=9

x'  1-9/2.1
-8/2 = -4

x" 1+9/2.1
 10/2 = 5
  • Usuário do Brainly
2014-05-22T17:50:10-03:00
X²-x-20=0

Δ=b²-4*a*c
Δ=1-4*1*-20
Δ=81

-b+-√Δ/2a

-(-1)+-9/2

1+-9/2

x´=1+9/2 =5
x''=1-9/2= -4