Question

d) 4 x2 - 5x + 8 = 0
e) 2x2 - 8x + 8 = 0
Preciso de ajuda apenas na D) e na E) porfavor

Answer 1

Resposta:

Explicação passo-a-passo:

D) 4x^2 - 5x + 8 = 0

a=4; B = - 5; c =8

∆= b^2-4ac

∆= (-5)^2- 4.4.8

∆= 25 - 4.32

∆= 25 - 128

∆= - 103

R.:

∆<0 (não há solução para os Números Reais)

___________________

e) 2x^2 - 8x + 8 = 0 (:2)

x^2 - 4x + 4 = 0

a = 1; b = -4; c = 4

∆= b^2-4ac

∆= (-4)^2-4.1.4

∆=16-16

∆= 0 (1 solução)

X = [- b+/- √∆]/2a

X = [-(-4)+/-0]/2.1

X = 4/2

X= 2

R.: {2}

Answer 2

Resposta:

A)x=2, x=3

1 2

B)x=2,x =6

1 2

C)x=-4, x=2

1 2

D)x=5/8+V103/8 i, x=-5/8V103/8 i

1 2

E)x=2

Explicação passo-a-passo:

A)x^2-5x+6=0

x^2-5x+6=0

x^2x-3x+6=0

x×(x-2)-3x+6=0

x^2-2x-3x+6=0

x×(x-2)-3(x-2)=0

x×(x-2)-3(x-2)=0

(x-2)×(x-3)=0

x-2=0

x-3=0

x-2=0

x-2+2=0+2

x=0×2

x-2+2=0+2

x=2

x-2=0

x-3=0

x=2

x-3=0

x-3+3=0+3

x=0+3

x-3+3=0+3

x=3

x-2=0

x-3=0

x=2

x=3

x=2, x=3

1 2

Resposta

x=2, x=3

1 2

B) x^2-8x+12=0

x^2-8x+12=0

x-2x=6x+12=0

x×(x-2)-6x+12=0

x^2-2x-6x+12=0

x×(x-2)-6(x-2)=0

x×(x-2)-6(x-2)=0

(x-2)×(x-6)=0

x-2=0

x-6=0

x-2=0

x-2+2=0+2

x=0+2

x-2+2=0+6

x=2

x-6=0

x-6+6=0+6

x=0+6

x6+6=0+6

x=6

x=2

x=6

x=2,x =6

1 2

Resposta

x=2,x=6

1 2

C) x^2+2x-8=0

x^2+2x-8=0

x^2+4x-2x-8=0

x×(x+4)-2x-8=0

x^2+4x-2x-8=0

x×(x+4)-2(x+4)=0

x×(x+4)-2(x+4)=0

(x+4)×(x-2)=0

x+4=0

x-2=0

x4=0

x+4-4=0-4

x=0-4

x+4=4=0-4

x=-4

x=-4

x-2=0

x-2+2=0+2

x=0+2

x-2+2=0+2

x=2

x+4=0

x-2=0

x=-4

x=2

x=-4x=2

1 2

Resposta

x=-4x=2

1 2

D) 4x^2-5x+8=0

4x^2-5x+8=0

4x^2+(-5)+8=0

a=4,b=-5,c=8

x=-(5)+V(-5)^2-4×4×8/2×4

x=-(-5)+V(-5)^2-4×4×8/2×4

x=5+V(-5)^2-4×4×8/2×4

x=-(-5)+V(5)^2-4×4×8/2×4

(-5)^2

5^2

5×5

25

(x=-(5)+V(-5)^2-4×4÷8/2×4

x=5+V(-5)^2-4×4×8/2×4

-4×4×8

-16×8

-128

x=-(-5)+V(-5)^2-4×4×8/2×4

x=+V25-128/2×4

x=(-5)+V-(-5^2)-4×4×8/2×4

x=5+V25-128/8

25-128

-(128-25)

-103

x=5+V25-128/8

x=5+V-103/8

V103

V103×(-1)

V103 V-1

V103 i

x=5+ V-103/8

x=5+ V103i/8

x=5+ V103i/8

x=5- V103i/8

5+ V103i/8

5/8+V103 i /8

5/8+V103/8 i

x=5-V103i/8

5-V103i/8

5/8-V103i/8

5/8V103i/8

x=5+V103i

x=5-V103 /8 i

x=5/8+V103/8 i

x=5/8-V103/8i

x=5/8+V103/8 i, x=5/8-V103/8 i

1 2

Resposta

x=5/8+V103/8 i, x-5/8-V103/8 i

1 2

E) 2x^2-8x+8=0

2x^2-8x+8=0

(2^2-8x+8)÷2=0÷2

2x^2÷2-8x÷2+8÷2=0+2

(2^2-8x+8)÷2=0÷2

2x^2÷2-8x÷2+8÷2=0

2x^2÷2-8x÷2+8÷2=0

x^2-8x÷2+8÷2=0

2x^2÷2-8x÷2+8÷2=

x^2-4x+8÷2=0

x^2-4x+4=0

x^2-4x+4

x^2-2×x×2+4

x^2-4x+4

x^2-2×x×2+2^2

(x-2)^2

x^2-4x+4=0

(x-2)^2=0

x-2=0

x-2+2=0+2

x=0+2

x-2+2=0+2

x=2

x-2=0

x=2

Resposta

x=2