Respuesta :
Answer:
The vertex is at (-3, 9).
The axis of symmetry is x = -3.
Step-by-step explanation:
We have the function:
[tex]f(x)=-x^2-6x[/tex]
And we want to determine its vertex and the equation of its axis of symmetry.
The vertex can be found with the following formulas:
[tex]\displaystyle \text{Vertex}=\left(-\frac{b}{2a}, f\left(-\frac{b}{2a}\right)\right)[/tex]
In this case, a = -1, b = -6, and c = 0.
Find the x-coordinate of the vertex:
[tex]\displaystyle x=-\frac{(-6)}{2(-1)}=-3[/tex]
To find the y-coordinate substitute this value back into the function:
[tex]\displaystyle f\left(-\frac{b}{2a}\right)=f(-3)=-(-3)^2-6(-3)=9[/tex]
So, the vertex of the equation is (-3, 9).
The axis of symmetry is goes through the vertex point. So, the equation for the axis of symmetry is simply the x-value. Therefore, the equation is:
[tex]x=-3[/tex]
Step-by-step explanation:
you can arrange f(x) as :
f(x) = 3(x^2 +3x ) +12 = 3 (x +1.5) ^2 + 5.25
so you can see the vertex is at (0,5.25) when x =-1.5
the axis symmetry then lies in x =-1.5
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