Respostas

2014-05-20T16:51:10-03:00

x² - 2x - 8 = 0

Δ= b²-4ac
Δ= (-2)² - 4.1.(-8)
Δ= 4+32
Δ= 36

x= -b+-√Δ / 2a
x= -(-2)+-√36 / 2.1
x= 2+-6 / 2
x'= 2+6 / 2 = 8 / 2 = 4
x''= 2-6 / 2 = -4 / 2 = -2

2014-05-20T16:54:46-03:00
X²-2x-8=0
vc deve resolver pela formula de baskara,ache o delta e depois o valor das raizes.
Δ=(-2)²-4.1.(-8)
Δ=4+32=  36

x= -(-2)+√36=
2+6/2=8/2=4
         2
x"=-(-2)-36= 2-6/2=-4/2= -2
  
         2

as raizes sao 4 e -2.