Question

Resolva as equações abaixo.

a) 9x²+8x-1=0

b) x²-2x+10=0

c) 9x²-4=0

Answer 1

a) 9x²+8x-1=0
Δ=8²-4.9.(-1)
Δ=64+36
Δ=100
x= -8+-√100/2.9
x= -8+-10/18
x¹= -8-10/18 = -18/18 = -1
x²= -8+10/18 = 2/18 = 1/9


b) x²-2x+10=0
Δ=(-2)²-4.1.10
Δ= 4-40
Δ= -36


c) 9x²-4=0
Δ= -4.9.(-4)
Δ= 144
x= +-√144/2.9
x= +-12/18
x= +-6/9
x= +-2/3