Question

Resolva as equações do 2 grau abaixo:

a) x²-16=0

b) x²-100= 0

c) 8x²- 32= 0

d) 4x²-36=0

e) 7x²+28x=0

f) x²- 2x-3=0​

Answer 1

Resposta:

a) a= 1, b=0, c= -16

Δ= b²-4.a.c

Δ= 0²- 4. 1. (-16)

Δ= 64

x= -b±√Δ/2.a

x= 0±√64/2.1

x'= 8/2= 4

x''= -8/2= -4

b) a= 1, b=0, c= 100

Δ= 0²-4.1.(-100)

Δ= 400

x= -0±√400/2.1

x'= 20/2=10

x''=-20/2= -10

c) a=8, b=0, c=-32

Δ= 0²-4.8.(-32)

Δ= 1024

x= -0±√1024/2.8

x'= 32/16=2

x''=-32/16= -2

d) a=4, b=0, c= -36

Δ= 0²-4.4.(-36)

Δ= 576

x= -0±√576/2.4

x'=24/8=3

x''= -24/8= -3

e) a= 7, b=28, c= 0

Δ= 28²-4.7.0

Δ= 784

x=-28±√784/2.7

x= -28±28/14

x'= -28+28/14= 0

x''= -28-28/14= -4

f) a= 1, b= -2, c= -3

Δ= (-2)²-4.1. (-3)

Δ= 4+12=16

x= -(-2)±√16/2.1

x= 2±4/2

x'= 2+4/2= 3

x''= 2- 4/2= -1