Question

quem poder me ajudar serei grato​

Answer 1

Resposta:

1.

a) 4x²+4x+1

b) x²+6x+9

c) 9x²-12x+4

d) x²-10x+25

e) 4x²+12x+9

2.

a) x²+3x+5 = 0

b) x = 0; -2

c)

d)

e) x²+1 = 3x

f) x = \|1,5

Explicação:

1.

a) (2x+1)² =

(2x+1)×(2x+1) =

[2x×2x]+[2x×1]+[1×2x]+[1×1] =

4x²+2x+2x+1 =

4x²+4x+1

b) (x+3)² =

(x+3)×(x+3) =

[x×x]+[x×3]+[3×x]+[3×3] =

x²+3x+3x+9 =

x²+6x+9

c) (3x-2)² =

(3x-2)×(3x-2) =

[3x×3x]+[3x×(-2)]+[-2×3x]+[-2×(-2)] =

9x²+(-6x)+(-6x)+4 =

9x²-6x-6x+4 =

9x²-12x+4

d) (x-5)² =

(x-5)×(x-5) =

[x×x]+[x×(-5)]+[-5×x]+[-5×(-5)] =

x²+(-5x)+(-5x)+25

x²-5x-5x+25 =

x²-10x+25

e) (2x+3)² =

(2x+3)×(2x+3) =

[2x×2x]+[2x×3]+[3×2x]+[3×3] =

4x²+6x+6x+9 =

4x²+12x+9

2.

a) x²+3x+5 = 0

b) x²+2x = 0

x²+2x-0 = 0

Δ = 2²-4×1×(-0)

Δ = 4-4×1×(-0)

Δ = 4-4×(-0)

Δ = 4+0

Δ = 4

x = -2+-\|4/2×1

x = -2+-2/2×1

x = -2+-2/2

x = -2+2/2

x = 0/2

x = 0

x = -2-2/2

x = -4/2

x = -2

c) 2x²+1 = 0

2x² = 0-1

2x² = -1

x² = -1÷2

x² = -0,5

d) 3x²+5x = 1

3x²+5x-1 = 0

Δ = 5²-4×3×(-1)

Δ = 25-4×3×(-1)

Δ = 25-12×(-1)

Δ = 25+12

Δ = 37

e) x²+1 = 3x

x² = 3x-1

x²-3x+1 = 0

Δ = (-3)²-4×1×1

Δ = 9-4×1×1

Δ = 9-4×1

Δ = 9-4

Δ = 5

f) 2x²-3 = 0

2x² = 0+3

2x² = 3

x² = 3÷2

x² = 1,5

x = \|1,5