Question

+ a) x2 - 6x + 9 = 0 b) X2 + 4x - 12 = ​

Answer 1

Resposta:

a) x² - 6x + 9 = 0

a = 1

b = - 6

c = 9

∆ = b² - 4.a.c

∆ = (-6)² - 4.1.9

∆ = 36 - 36

∆ = 0

x = - b ± √∆ / 2.a

x = -(-6) ± √0 / 2.1

x = 6 ± 0 / 2

x' = 6 + 0 = 6 ÷ 2 = 3

x" = 6 - 0 = 6 ÷ 2 = 3

S = {3}

b) x² + 4x - 12 = 0

a = 1

b = 4

c = - 12

∆ = b² - 4.a.c

∆ = 4² - 4.1.(-12)

∆ = 16 - 4.(-12)

∆ = 16 + 48

∆ = 64

x = - b ± √∆ / 2.a

x = - 4 ± √64 / 2.1

x = - 4 ± 8 / 2

x' = - 4 - 8 = (-12) ÷ 2 = - 6

x" = - 4 + 8 = 4 ÷ 2 = 2

S = {-6,2}