The vertex of this parabola is at [tex]\((-2, 5)\)[/tex]. Which of the following could be its equation?

A. [tex]\( y = 3(x + 2)^2 - 5 \)[/tex]
B. [tex]\( y = 3(x - 2)^2 + 5 \)[/tex]
C. [tex]\( y = 3(x - 2)^2 - 5 \)[/tex]
D. [tex]\( y = 3(x + 2)^2 + 5 \)[/tex]



Answer :

To determine the correct equation of a parabola with a vertex at [tex]\((-2, 5)\)[/tex], we can use the vertex form of a parabola's equation:

[tex]\[ y = a(x - h)^2 + k \][/tex]

where [tex]\((h, k)\)[/tex] is the vertex of the parabola.

Given that the vertex is [tex]\((-2, 5)\)[/tex]:
- [tex]\(h = -2\)[/tex]
- [tex]\(k = 5\)[/tex]

Substituting these values into the vertex form, we get:

[tex]\[ y = a(x - (-2))^2 + 5 \][/tex]
[tex]\[ y = a(x + 2)^2 + 5 \][/tex]

Now, let's analyze each given option to see which one matches this form:
- Option A: [tex]\(y = 3(x + 2)^2 - 5\)[/tex]

In this case, [tex]\(k = -5\)[/tex], which does not match our vertex form where [tex]\(k = 5\)[/tex]. So, this is incorrect.

- Option B: [tex]\(y = 3(x - 2)^2 + 5\)[/tex]

In this case, [tex]\(h = 2\)[/tex], which does not match our vertex form where [tex]\(h = -2\)[/tex]. So, this is incorrect.

- Option C: [tex]\(y = 3(x - 2)^2 - 5\)[/tex]

In this case, both [tex]\(h = 2\)[/tex] and [tex]\(k = -5\)[/tex] are incorrect. Thus, this option does not match the given vertex. So, this is incorrect.

- Option D: [tex]\(y = 3(x + 2)^2 + 5\)[/tex]

Here, [tex]\(h = -2\)[/tex] and [tex]\(k = 5\)[/tex], which exactly match the values in our vertex form. Therefore, this is the correct option.

Based on the analysis, the correct equation of the parabola with vertex [tex]\((-2, 5)\)[/tex] is:

[tex]\[ \boxed{y = 3(x + 2)^2 + 5} \][/tex]