Question

resolva as seguintes equacoes do 2 grau
ajuda pfv^^...​

Answer 1

Resposta:

A) x2 - 5x +6 = 0

a = 1

b =  -5

c = 6

Δ = (-5)² - 4 x 1 x 6

Δ = 25 - 4 x 1 x 6

Δ = 25 - 24

Δ = 1

bhaskara

x = -b±√Δ/2a

x1 = 5 + 1 = 6/2 = 3

        2

x2 = 5 - 1 = 4/1 = 2

S = {2,3}

B) x² - 8x + 12 = 0

a = 1

b = -8

c = 12

Δ = (-8)² - 4 x 1 x 12

Δ = 64 - 4 x 1 x 12

Δ = 64 - 48

Δ = 16

Bhaskara

x =  -b±√Δ/2a

x1 = 8 + 4 = 12/2 = 6

x2 = 8 - 4 = 4/2 = 2

S = {2,6}

C) x² + 2x - 8 = 0

a = 1

b = 2

c = -8

Δ = 2² - 4.1.(-8)

Δ = 4 + 32

Δ = 36

Bhaskara

x = -b±√Δ/2a

x1 = -2 + 6 = 4/2 =  2

x2 = -2 - 6 = -8/2 = -4

S = {-4,2}

D)

a = 1

b = -5

c = 8

Δ = (-5)² - 4.1.8

Δ = 25 - 32

Δ = -7

Quando o delta e negativo não há raízes reais!

E)  2x² - 8x + 8 = 0

a = 1

b = -4

c = 4

Δ = (-4)² - 4 x 1 x 4

Δ = 16 - 4 x 1 x 4

Δ = 16 - 16 = 0

Bhaskara

x = -b±√Δ/2a

x1 = 4 + 0 = 4/2 = 2

x2 = 4 - 0 = 4/2 = 2

S = {2}

F) x² - 4x - 5 = 0

a = 1

b = -4

c = -5

Δ = (-4)² - 4.1.(-5)  

Δ = 16 + 20  

Δ = 36

Bhaskara

x = -b±√Δ/2a

x1 = 4 - 6 = -2/2 = -1

x2 = 4 + 6 = 10/2 = 5

S = {-1,5}

G)  -x² + x + 12 = 0

a = 1

b = -1

c = -12

Δ = (-1)² - 4 x 1 x -12

Δ = 1 - 4 x 1 x -12

Δ = 1 + 48

Δ = 49

x = -b±√Δ/2a

x1 = 1 + 7 = 8/2 = 4

x2 = 1 - 7 =  -6/2 = -3

S = {-3,4}

I)

-x² + 6x - 5 = 0

a = -1

b =  6

c =  -5

Δ= 6² - 4.-1.-5

Δ = 36-20

Δ = 16

x = -b±√Δ/2a

x1 = -6 + 4 = 2/2 = 1

x2 = -6 - 4 = -10/-2 = 5

S =  {5,1}

J) 6x² + x - 1 = 0

a  = 6

b = 1

c = -1

Δ = (1)² - 4.6.(-1)

Δ = 1 + 24

Δ = 25

x = -b±√Δ/2a

x1 = -1 + 5 = 4/12 Divida por 2 2/6 dividida por 2  1/3

x2 = -1 - 5 = -6/12 divida por 2 -3/6 divida por 3 -1/2

S = {-1/2,1/3}

K) 3x² - 7x + 2 = 0

a = 3

b = -7

c =  2

Δ = (-7)² - 4 x 1 x 2

Δ = 49 - 4 x 3 x 2

Δ = 49 - 24

Δ = 25

x = -b±√Δ/2a

x1 = 7 + 5 = 12/6 = 2

x2 = 7 - 5 = 2/6 dividido por 2 = 1/3

S = {1/3,2}