Question
Use the equation \( y=x^{2}-9 \) to answer parts a) through g) below. a) Determine whether the parabola will open upward or downward. T. The parabola will open downward. b) Find the equation of the axis of symmetry. The axis of symmetry is \( x=0 \). (Type an equation.) c) Find the vertex. The vertex of the parabola is (Type an ordered pair.)
Ask by Savage Robbins. in the United States
Feb 20,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
- a) The parabola opens upward.
- b) The axis of symmetry is \( x = 0 \).
- c) The vertex is \( (0, -9) \).
Solution
Let's analyze the given equation of the parabola, \( y = x^2 - 9 \), step by step.
### a) Determine whether the parabola will open upward or downward.
The general form of a parabola is \( y = ax^2 + bx + c \). In this case, we have:
- \( a = 1 \)
- \( b = 0 \)
- \( c = -9 \)
Since \( a > 0 \), the parabola opens **upward**.
### b) Find the equation of the axis of symmetry.
The axis of symmetry for a parabola in the form \( y = ax^2 + bx + c \) is given by the formula:
\[
x = -\frac{b}{2a}
\]
Substituting the values of \( a \) and \( b \):
\[
x = -\frac{0}{2 \cdot 1} = 0
\]
Thus, the equation of the axis of symmetry is:
\[
x = 0
\]
### c) Find the vertex.
The vertex of a parabola can be found using the coordinates:
\[
\left(-\frac{b}{2a}, f\left(-\frac{b}{2a}\right)\right)
\]
We already calculated \( -\frac{b}{2a} = 0 \). Now we need to find \( f(0) \):
\[
f(0) = 0^2 - 9 = -9
\]
Thus, the vertex of the parabola is:
\[
(0, -9)
\]
### Summary of Answers:
- a) The parabola will open **upward**.
- b) The axis of symmetry is \( x = 0 \).
- c) The vertex of the parabola is \( (0, -9) \).
Answered by UpStudy AI and reviewed by a Professional Tutor
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The Deep Dive
The equation \( y = x^2 - 9 \) represents a parabola that opens upward because the coefficient of \( x^2 \) is positive (in this case, it is 1). The vertex of this parabola can be found by setting \( y = 0 \) and solving for \( x \). Rearranging yields \( x^2 = 9 \), so \( x = 0 \) is indeed correct, but the vertex corresponds to the minimum \( y \) value, which occurs at \( \left(0, -9\right) \). So, to summarize: - The parabola opens upward. - The vertex of the parabola is at \( (0, -9) \).