Question

determine as raizes ou zerosda função quadratica f(×)=×2-4×-5​

Answer 1

Resposta:

f(x) = x² - 4x - 5

x² - 4x - 5 =0

coeficientes

a = 1

b = -4

c = - 5

Δ = b² -4ac

Δ = (-4)² - 4(1)(-5)

Δ = 16 + 20

Δ = 36

$x={-b\pm\sqrt{\Delta} \over2a}\\ \\ x={-(-4)\pm\sqrt{36} \over2.(1)}={4\pm6\over2}\\ \\ x'={4-6\over2}=-{2\over2}=-1\\ \\ x"={4+6\over2}={10\over2}=5$

As raizes são -1 e 5