Question

1) Calcule as raízes das funções:

y = x² - 2x - 3
y = x² - 6x + 9
y = x² - 4x + 3

Answer 1

Resposta:

• y = x² - 2x - 3

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

S = {-1, 3}

• y = x² - 6x + 9

a = 1, b = -6, c = 9

Δ = (-6)^2 - 4*1*9

Δ = 36 - 36 = 0

x = -(-6) ± √0 / 2*1

x = 6 ± 0 /2

x = 3

S = {3}

• y = x² - 4x + 3

a = 1, b = -4, c = 3

Δ = (-4)^2 - 4*1*3

Δ = 16 - 12 = 4

x = -(-4) ± √4 / 2*1

x = 4 ± 2 /2

x' = 4+2 /2 = 3

x" = 4-2 / 2 = 1

S = {1, 3}