Use the image to answer the question.

A coordinate plane shows a parabola that opens downward. The x-axis ranges from 0 to 15 in increments of 5. The y-axis ranges from 0 to 15 in increments of 5.

The graph shows the trajectory of a firework. Which equation in vertex form matches this graph?

(1 point)
Responses

y=−12(x−5)2+10
y equals negative Start Fraction 1 over 2 End Fraction left parenthesis x minus 5 right parenthesis squared plus 10

y=12(x+5)2+10
y equals Start Fraction 1 over 2 End Fraction left parenthesis x plus 5 right parenthesis squared plus 10

y=−12(x−5)2−10
y equals negative Start Fraction 1 over 2 End Fraction left parenthesis x minus 5 right parenthesis squared minus 10

y=12(x−5)2+10

1 answer

To determine which equation in vertex form matches the given graph of a parabola that opens downward, we need to analyze the parameters of vertex form, which is:

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

In this equation:

  • \( (h, k) \) is the vertex of the parabola.
  • \( a \) determines the direction and width of the parabola: if \( a < 0 \), the parabola opens downward, and if \( a > 0 \), it opens upward.

Based on your description:

  • The parabola opens downward, indicating \( a < 0 \).
  • The vertex appears to be at \( (5, 10) \).

Now, let's evaluate the options provided:

  1. \( y = -12(x - 5)^2 + 10 \):

    • This is a downward opening parabola with vertex \( (5, 10) \) (correct form).
  2. \( y = \frac{-1}{2}(x - 5)^2 + 10 \):

    • This is also a downward opening parabola with vertex \( (5, 10) \) (correct form but different \( a \)).
  3. \( y = -12(x - 5)^2 - 10 \):

    • This is a downward opening parabola, but the vertex is at \( (5, -10) \) (incorrect vertex).
  4. \( y = 12(x - 5)^2 + 10 \):

    • This is an upward opening parabola (incorrect direction).

Given this analysis, the equations that correctly feature a downward-opening parabola with the vertex at \( (5, 10) \) are the first two options.

If you are only looking for one correct response, the best match would be:

\( y = -12(x - 5)^2 + 10 \)

This option maintains the downward trajectory and has the correct vertex.