Answer:
Please refer to the attached image for the graph of given function.
Step-by-step explanation:
Given the equation:
[tex]-x^{2} +4x+12[/tex]
Let us rewrite by letting it equal to [tex]y[/tex].
[tex]y=-x^{2} +4x+12[/tex]
Now, we can see that it is a quadratic equation and it is known that a quadratic equation has a graph of parabola.
Let us compare the given equation with standard quadratic equation:
[tex]y=ax^{2} +bx+c[/tex]
we get:
[tex]a = -1\\b = 4\\c = 12[/tex]
Coefficient of [tex]x^{2}[/tex] is negative 1, so the parabola will open downwards.
Axis of symmetry: It is the line which will divide the parabola in two equal congruent halves.
Formula for axis of symmetry is:
[tex]x = -\dfrac{b}{2a}[/tex]
[tex]x = -\dfrac{4}{2(-1)}\\\Rightarrow x=2[/tex]
It is shown as dotted line in the image attached in the answer area.
Axis of symmetry will also contain the vertex of the parabola.
It is a downward parabola so vertex will be the highest point on this parabola.
Putting x = 2 in the equation of parabola:
[tex]y=-2^{2} +4\times 2+12\\\Rightarrow y =16[/tex]
So, vertex will be at P(2, 16).
Now, let us find points of parabola to sketch graph:
put x = 0, [tex]y=-0^{2} +4\times 0+12=12[/tex]
Another point is Y(0,12)
Now, let us put y = 0, it will give us two points because the equation is quadratic in x.
[tex]0=-x^{2} +4x+12\\\Rightarrow -x^{2} +6x-2x+12=0\\\Rightarrow -x(x -6)-2(x-6)=0\\\Rightarrow (-x-2)(x-6)=0\\\Rightarrow x = -2, 6[/tex]
So, other two points are X1(-2, 0) and X2(6,0).
If we plot the points P, Y, X1 and X2 we get a graph as attached in the image in answer area.
