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

(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.

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

(0.5,9) is the high point on the parabola.
left parenthesis 0.5 comma 9 right parenthesis is the high point on the parabola.

(−1,−1) is the low point on the parabola.

1 answer

To determine the high or low point of the parabola represented by the quadratic equation \( y = -6x^2 + 3x + 8 \), we can first find the vertex of the parabola. The vertex occurs at \( x = -\frac{b}{2a} \) where \( a \) and \( b \) are the coefficients in the standard quadratic equation \( y = ax^2 + bx + c \).

Given:

  • \( a = -6 \)
  • \( b = 3 \)

We can calculate the x-coordinate of the vertex:

\[ x = -\frac{b}{2a} = -\frac{3}{2 \cdot -6} = -\frac{3}{-12} = \frac{1}{4} = 0.25 \]

Next, we substitute \( x = 0.25 \) into the quadratic equation to find the corresponding y-coordinate:

\[ y = -6(0.25)^2 + 3(0.25) + 8 \] \[ = -6(0.0625) + 0.75 + 8 \] \[ = -0.375 + 0.75 + 8 \] \[ = 8.375 \]

Thus, the vertex of the parabola is \( (0.25, 8.375) \).

Since the coefficient of \( x^2 \) is negative (\( a = -6 \)), the parabola opens downwards, indicating that the vertex represents the high point on the parabola.

So, the correct response is:

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