Question

1) Calcular os zeros das seguintes funções:
a) f(x) = – x² + 4x – 4

b) f(x) = 36x2 + 12x + 1

c) f(x) = (2x + 3).(x – 2)

Answer 1

a) f(x) = – x² + 4x – 4

∆ = 4² - 4 -1 -4

∆ = 16 - 16

-4 ± 0 / -2

x' e x" = -4/-2 = 2

b) f(x) = 36x² + 12x + 1

∆ = 12² - 4 36 1

∆ = 144 - 144

∆ = 0

- 12 ± 0 / 2.36

- 12 / 72

x' e x" = -12/72 = 1/18

c) f(x) = (2x + 3).(x – 2)

2x² - 4x + 3x - 6 = 0

2x² - x - 6 = 0

∆ = -1² - 4 2 -6

∆ = 1 + 48

∆ = 49

- (-1) ± √49 / 2.2

1 ± 7 / 4

x' = 8/4 = 2

x" = 6/4 = 3/2