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 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 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
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1 answer

To determine which equation in vertex form matches the graph of the firework trajectory, we need to analyze the characteristics of a parabola in vertex form, which is given by:

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

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

Since the parabola shown opens downward, the value of \( a \) must be negative.

Reviewing the provided options:

  1. y = 12(x − 5)² + 10 → Opens upwards (a positive value: 12)
  2. y = (1/2)(x + 5)² + 10 → Opens upwards (a positive value: 1/2)
  3. y = −12(x − 5)² + 10 → Opens downwards (a negative value: -12)
  4. y = −(1/2)(x − 5)² − 10 → Opens downwards (a negative value: -1/2)

Since the graph opens downward, we look for options 3 and 4.

Next, we need to identify the vertex. If the vertex appears to be at the point (5, 10) based on your description, then option 3 is the most appropriate because it maintains the vertex at \( (5, 10) \) (since it follows the form):

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

Thus, the final answer is:

y = -12(x − 5)² + 10.