Respuesta :
Answer:
vertex = (4, - 25 )
Step-by-step explanation:
Given a quadratic function in standard form : f(x) = ax² + bx + c : a ≠ 0
The the x- coordinate of the vertex is
[tex]x_{V}[/tex] = - [tex]\frac{b}{2a}[/tex]
f(x) = x² - 8x - 9 ← is in standard form
with a = 1, b = - 8, thus
[tex]x_{V}[/tex] = - [tex]\frac{-8}{2}[/tex] = 4
Substitute x = 4 into f(x) for corresponding value of y
f(4) = 4² - 8(4) - 9 = 16 - 32 - 9 = - 25
vertex = (4, - 25 )
Answer:
vertex is (4,-25)
Step-by-step explanation:
[tex]f(x) = x^2 - 8x - 9[/tex]
To find out the vertex we use formula
[tex]x=\frac{-b}{2a}[/tex]
From the given f(x), the value of a=1, b=-8 and c=-9
Plug in the values in the formula
[tex]x=\frac{-(-8)}{2(1)}[/tex]
x=4
Now find the value of y
plug in 4 for x in f(x)
[tex]f(4) = 4^2 - 8(4)- 9=-25[/tex]
The value of y is -25
The vertex is (4,-25)
