Q:

Which of the equations below could be the equation of this parabola

Accepted Solution

A:
Answer:  [tex]y=-4x^2[/tex]  is the equation of this parabola.Step-by-step explanation:Let us consider the equation[tex]y=-4x^2[/tex][tex]\mathrm{Domain\:of\:}\:-4x^2\::\quad \begin{bmatrix}\mathrm{Solution:}\:&\:-\infty \:<x<\infty \\ \:\mathrm{Interval\:Notation:}&\:\left(-\infty \:,\:\infty \:\right)\end{bmatrix}[/tex][tex]\mathrm{Range\:of\:}-4x^2:\quad \begin{bmatrix}\mathrm{Solution:}\:&\:f\left(x\right)\le \:0\:\\ \:\mathrm{Interval\:Notation:}&\:(-\infty \:,\:0]\end{bmatrix}[/tex][tex]\mathrm{Axis\:interception\:points\:of}\:-4x^2:\quad \mathrm{X\:Intercepts}:\:\left(0,\:0\right),\:\mathrm{Y\:Intercepts}:\:\left(0,\:0\right)[/tex]As[tex]\mathrm{The\:vertex\:of\:an\:up-down\:facing\:parabola\:of\:the\:form}\:y=a\left(x-m\right)\left(x-n\right)[/tex][tex]\mathrm{is\:the\:average\:of\:the\:zeros}\:x_v=\frac{m+n}{2}[/tex][tex]y=-4x^2[/tex][tex]\mathrm{The\:parabola\:params\:are:}[/tex][tex]a=-4,\:m=0,\:n=0[/tex][tex]x_v=\frac{m+n}{2}[/tex][tex]x_v=\frac{0+0}{2}[/tex][tex]x_v=0[/tex][tex]\mathrm{Plug\:in}\:\:x_v=0\:\mathrm{to\:find\:the}\:y_v\:\mathrm{value}[/tex][tex]y_v=-4\cdot \:0^2[/tex][tex]y_v=0[/tex]Therefore, the parabola vertex is[tex]\left(0,\:0\right)[/tex][tex]\mathrm{If}\:a<0,\:\mathrm{then\:the\:vertex\:is\:a\:maximum\:value}[/tex][tex]\mathrm{If}\:a>0,\:\mathrm{then\:the\:vertex\:is\:a\:minimum\:value}[/tex][tex]a=-4[/tex][tex]\mathrm{Maximum}\space\left(0,\:0\right)[/tex]so,[tex]\mathrm{Vertex\:of}\:-4x^2:\quad \mathrm{Maximum}\space\left(0,\:0\right)[/tex]Therefore,  [tex]y=-4x^2[/tex]  is the equation of this parabola. The graph is also attached.