Given the table of values, complete the table for the quadratic equation y=−6x2+3x+8 to find the values of the high or low point of the parabola.

x y
−1 −1
−0.75 2.375
−0.5 5
−0.25
0 8
0.25 8.375
0.5
0.75
1 5
Which of the following is correct?

(1 point)
Responses

(−1,−1) is the low point on the parabola.
left parenthesis negative 1 comma negative 1 right parenthesis is the low point on the parabola.

(0.25,8.375) is the high point on the parabola.
left parenthesis 0.25 comma 8.375 right parenthesis is the high point on the parabola.

(0.25,8.375) is the low point on the parabola.
left parenthesis 0.25 comma 8.375 right parenthesis is the low point on the parabola.

(0.5,9) is the high point on the parabola.

1 answer

To determine the high or low point of the parabola defined by the equation \( y = -6x^2 + 3x + 8 \), we need to find the vertex of the parabola. The vertex will give us the maximum or minimum value of the quadratic function since it opens downwards (the coefficient of \( x^2 \) is negative).

The x-coordinate of the vertex can be found using the formula:

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

where \( a = -6 \) and \( b = 3 \). Substituting these values into the formula:

\[ x = -\frac{3}{2(-6)} = -\frac{3}{-12} = \frac{1}{4} = 0.25 \]

Now, we can find the corresponding y-coordinate by substituting \( x = 0.25 \) back into the quadratic equation:

\[ y = -6(0.25)^2 + 3(0.25) + 8 \]

Calculating \( (0.25)^2 \):

\[ (0.25)^2 = 0.0625 \]

Thus, we have:

\[ y = -6(0.0625) + 3(0.25) + 8 = -0.375 + 0.75 + 8 = 8.375 \]

So the vertex of the parabola is at the point \( (0.25, 8.375) \).

Since the parabola opens downwards (as indicated by the negative \( a \)), this means that \( (0.25, 8.375) \) is the maximum point (or high point) of the parabola.

Now, let's fill in the missing values in the table:

  • For \( x = -0.25 \):

\[ y = -6(-0.25)^2 + 3(-0.25) + 8 = -6(0.0625) - 0.75 + 8 = -0.375 - 0.75 + 8 = 6.875 \]

  • For \( x = 0.5 \):

\[ y = -6(0.5)^2 + 3(0.5) + 8 = -6(0.25) + 1.5 + 8 = -1.5 + 1.5 + 8 = 8 \]

  • For \( x = 0.75 \):

\[ y = -6(0.75)^2 + 3(0.75) + 8 = -6(0.5625) + 2.25 + 8 = -3.375 + 2.25 + 8 = 6.875 \]

Now we have our completed table of values:

| x | y | |------|-------| | -1 | -1 | | -0.75| 2.375 | | -0.5 | 5 | | -0.25| 6.875 | | 0 | 8 | | 0.25 | 8.375 | | 0.5 | 8 | | 0.75 | 6.875 | | 1 | 5 |

Now, based on this information, the correct response is:

(0.25, 8.375) is the high point on the parabola.

Thus the correct response is:

(0.25, 8.375) is the high point on the parabola.