The table describes the quadratic function [tex]p(x)[/tex].

[tex]\[
\begin{tabular}{|l|l|}
\hline
$x$ & $p(x)$ \\
\hline
-1 & 10 \\
\hline
0 & 1 \\
\hline
1 & -2 \\
\hline
2 & 1 \\
\hline
3 & 10 \\
\hline
4 & 25 \\
\hline
5 & 46 \\
\hline
\end{tabular}
\][/tex]

What is the equation of [tex]p(x)[/tex] in vertex form?



Answer :

To find the equation of the quadratic function [tex]\( p(x) \)[/tex] in vertex form, we follow these steps:

1. Identify the Vertex:
From the provided table, observe the symmetry of the values. The minimum value (-2) at [tex]\( x = 1 \)[/tex] and equal distances from this point suggest that the vertex lies at [tex]\( x = 2 \)[/tex], where [tex]\( p(2) = 1 \)[/tex].

2. Vertex Form:
The vertex form of a quadratic equation is:
[tex]\[ p(x) = a(x - h)^2 + k \][/tex]
where [tex]\( (h, k) \)[/tex] is the vertex of the parabola.
Here, [tex]\( h = 2 \)[/tex] and [tex]\( k = 1 \)[/tex], so the equation becomes:
[tex]\[ p(x) = a(x - 2)^2 + 1 \][/tex]

3. Determine the Coefficient [tex]\( a \)[/tex]:
We can use another point from the table to find [tex]\( a \)[/tex]. Let's use the point [tex]\( (1, -2) \)[/tex].

Substitute [tex]\( x = 1 \)[/tex] and [tex]\( p(x) = -2 \)[/tex] into the vertex form:
[tex]\[ -2 = a(1 - 2)^2 + 1 \][/tex]
Simplify and solve for [tex]\( a \)[/tex]:
[tex]\[ -2 = a(-1)^2 + 1 \][/tex]
[tex]\[ -2 = a + 1 \][/tex]
[tex]\[ -2 - 1 = a \][/tex]
[tex]\[ a = -3 \][/tex]

4. Write the Final Equation:
Substitute [tex]\( a = -3 \)[/tex] back into the vertex form:
[tex]\[ p(x) = -3(x - 2)^2 + 1 \][/tex]

Therefore, the equation of [tex]\( p(x) \)[/tex] in vertex form is:
[tex]\[ p(x) = -3(x - 2)^2 + 1 \][/tex]