Question

Calcule os Zeros das funções
a) f(x)=x²+3x+2
b) f(x)=x²-3x-4

Answer 1

a) x² + 3x+2 = 0 
Δ = 9 - 8
Δ = 1

x= -3 +-√1/2
x= -3 +-1/2

x' = -3+1/2
x' = -2/2 = -1

x'' = -3-1/2
x'' = -4/2 = - 2

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b) x² - 3x - 4 = 0 
Δ = 9 + 16
Δ = 25

x = 3 +-√25/2
x = 3 +-5/2

x' = 3+5/2
x' = 8/2 = 4

x'' = 3-5/2
x'' = -2/2 = -1                           ok