Question

Dada a função do 2° grau F(x) = x 2 + 2x - 8 determine as raizes e o do vértice


A) x 1 = -4 ; x 2 = 1 e V(-9, 1)


B) x 1 = -4 ; x 2 = 2 e V(-1, -9)


C) x 1 =4 ; x 2 = -2 e V(-1, -9)


D) x 1 = 4 ; x 2 = -1 e V(-9, 1)


E) x 1 = 4 ; x 2 = -1 e V(-1, 9)

Answer 1

Resposta:

Opção B

Explicação passo-a-passo:

x ² + 2x - 8=0

a=1

b=2

c=-8

∆=b²-4ac

∆=2²-4*1*-8

∆=4+32

∆=36

-b±√∆/2a

-2±√36/2*1

-2±6/2

x¹=-2+6/2=4/2=>2

x²=-2-6/2=-8/2=>-4

Xv=-b/2a

Xv=-2/2*1

Xv=-2/2

Xv=-1

Yv=-∆/4a

Yv=-36/4*1

Yv=-36/4

Yv=-9

Answer 2

Resposta:

x1=$\frac{-2+-\sqrt{2^{2} -4*1*-8} }{2*1}$

x1=$\frac{-2+-\sqrt{4+32} }{2}$

x1=

$\frac{-2+-6}{2} \\\frac{4}{2} =2$

x2=$\frac{-2+-6}{2} \\\frac{-8}{2} =-4$

VERtices =  

vertice x=

$-\frac{b}{2*a} \\-\frac{2}{2} \\=-1$

vertice y

$-\frac{2^{2} -4*1*-8}{4*1} \\-\frac{36}{4} =-9$

Explicação passo a passo: