Question

POR FAVOOOOOOOR!!! me ajuda​

Answer 1

Resposta:

a) 2x² - 14x + 20 = 0

a 2 b -14 c 20

Δ = (-14)² - 4 · 2 · 20

Δ = 196 - 160

Δ = 36

x = - (-14) ± $\sqrt{36}$/2 · 2

x = 14 ± 6/4

x¹ = 14 + 6/4 = 20/4 = 5

x² = 14 - 6/4 = 8/4 = 2

b) -x² + 3x + 4

a -1 b 3 c 4

Δ = 3² - 4 · (-1) · 4

Δ = 9 + 16

Δ = 25

x = - 3 ± $\sqrt{25}$/ 2 · (-1)

x = -3 ± 5/-2

x¹ = -3 - 5/-2 = -8/-2 = 4

x² = -3 + 5/-2 = -2/2 = -1

c) x² + 4x + 3

a 1 b 4 c 3

Δ = 4² - 4 · 1 · 3

Δ = 16 - 12

Δ = 4

x = -4 ± $\sqrt{4}$/2

x = -4 ± 2/2

x¹ = -4 - 2/2 = -6/2 = -3

x² = - 4 + 2/2 = -2/2 = -1

d) -x² + 6x - 9

a -1 b 6 c -9

Δ = 6² - 4 · (-1) · (-9)

Δ = 36 - 36

Δ = 0

x = -6 ± $\sqrt{0}$/2 · (-1)

x = -6 ± 0/-2

x¹ = -6 + 0/-2 = -6/-2 = 3

x² = -6 - 0/-2 = -6/-2 = 3

e) x² - 4

a 1 b 0 c -4

Δ = 0² - 4 · 1 ·  (-4)

Δ = 0 + 16

Δ = 16

x = -0 ±$\sqrt{16}$/2

x = 0 ± 4/2

x¹ = 0 - 4/2 = -4/2 = -2

x² = 0 + 4/2 = 4/2 = 2