To analyze the quadratic function \( y = x^2 - 8x \), we will find the vertex, x-intercepts, and y-intercept.
1. Vertex
The vertex of a quadratic function in the form \( y = ax^2 + bx + c \) can be calculated using the formula: \[ x = -\frac{b}{2a} \]
In this case, \( a = 1 \) and \( b = -8 \): \[ x = -\frac{-8}{2 \cdot 1} = \frac{8}{2} = 4 \]
To find the y-coordinate of the vertex, substitute \( x = 4 \) into the function: \[ y = (4)^2 - 8(4) = 16 - 32 = -16 \]
Thus, the vertex is: \[ \text{Vertex: } (4, -16) \]
2. X-Intercepts
To find the x-intercepts, set \( y = 0 \): \[ 0 = x^2 - 8x \] Factoring gives: \[ 0 = x(x - 8) \] Setting each factor to zero: \[ x = 0 \quad \text{or} \quad x - 8 = 0 \rightarrow x = 8 \]
Thus, the x-intercepts are: \[ \text{X-Intercepts: } (0, 0) \text{ and } (8, 0) \]
3. Y-Intercept
To find the y-intercept, set \( x = 0 \): \[ y = (0)^2 - 8(0) = 0 \]
Thus, the y-intercept is: \[ \text{Y-Intercept: } (0, 0) \]
Summary of Key Points
- Vertex: \( (4, -16) \)
- X-Intercepts: \( (0, 0) \) and \( (8, 0) \)
- Y-Intercept: \( (0, 0) \)
Conclusion
Now, looking at the provided options:
- The responses indicating a vertex of (4, -16) are correct.
- The x-intercepts should indeed be (0, 0) and (8, 0) with the y-intercept also being (0, 0).
Correct selection reflecting this would be:
- Vertex: (4, -16)
- X-Intercepts: (0, 0) and (8, 0)
- Y-Intercept: (0, 0)