Functions & Their Graphs Online Practice

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Question
A volleyball is served from a height of 6 feet with an initial velocity of 33 feet per second. The situation is modeled using the function h=−6t2+33t+6
, where h is the height in feet and t is time in seconds. Using the function, which ordered pair represents the vertex?(1 point)
Responses

(51.375,2.75)
left parenthesis 51.375 comma 2.75 right parenthesis

(5.676,0)
left parenthesis 5.676 comma 0 right parenthesis

(0,6)
left parenthesis 0 comma 6 right parenthesis

(2.75,51.375)
left parenthesis 2.75 comma 51.375 right parenthesis
Remaining Attempts : 3
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1 answer

To find the vertex of the quadratic function given by \(h(t) = -6t^2 + 33t + 6\), we can use the formula for the t-coordinate of the vertex, which is given by:

\[ t = -\frac{b}{2a} \]

where \(a\) is the coefficient of \(t^2\) and \(b\) is the coefficient of \(t\).

In your function:

  • \(a = -6\)
  • \(b = 33\)

Plugging in the values:

\[ t = -\frac{33}{2(-6)} = \frac{33}{12} = 2.75 \]

Next, we need to find the height \(h\) at \(t = 2.75\).

Substituting \(t = 2.75\) back into the function:

\[ h(2.75) = -6(2.75)^2 + 33(2.75) + 6 \] Calculating \( (2.75)^2 \):

\[ (2.75)^2 = 7.5625 \] Now substituting back into the equation:

\[ h(2.75) = -6(7.5625) + 33(2.75) + 6 \] Calculate \(-6(7.5625)\):

\[ -6(7.5625) = -45.375 \] Calculate \(33(2.75)\):

\[ 33(2.75) = 90.75 \] Now combine these values:

\[ h(2.75) = -45.375 + 90.75 + 6 \] Calculating this gives:

\[ h(2.75) = 51.375 \]

Thus, the vertex of the function is at:

\[ (2.75, 51.375) \]

Therefore, the correct response is:

(2.75, 51.375)