Math Problem Statement

k(x)=−x2+6x−8k(x)=−x2+6x−8

Step 3 of 4: 

Find two points on the graph of the parabola other than the vertex and x-intercepts.

Solution

To find two points on the graph of the parabola represented by the function k(x)=x2+6x8k(x) = -x^2 + 6x - 8 other than the vertex and xx-intercepts, we can choose any xx-values and compute the corresponding yy-values using the function k(x)k(x).

Step-by-Step Solution:

  1. Choose two xx-values:

    • We can choose any two xx-values that are not the xx-intercepts or the xx-coordinate of the vertex. To avoid those, let's first find the vertex and the xx-intercepts.
  2. Find the vertex: The vertex of a parabola given by ax2+bx+cax^2 + bx + c occurs at x=b2ax = -\frac{b}{2a}.

    For k(x)=x2+6x8k(x) = -x^2 + 6x - 8:

    • a=1a = -1
    • b=6b = 6

    So, the xx-coordinate of the vertex is: x=62(1)=62=3x = -\frac{6}{2(-1)} = \frac{6}{2} = 3

    The xx-coordinate of the vertex is x=3x = 3.

  3. Find the xx-intercepts: The xx-intercepts occur where k(x)=0k(x) = 0. To find them, solve the equation: x2+6x8=0-x^2 + 6x - 8 = 0

    Rearrange and factor the quadratic: x26x+8=0x^2 - 6x + 8 = 0 (x2)(x4)=0(x - 2)(x - 4) = 0

    So, the xx-intercepts are at x=2x = 2 and x=4x = 4.

  4. Choose two other xx-values: We need to choose two xx-values different from 2, 3, and 4. Let's choose x=0x = 0 and x=1x = 1.

  5. Compute the corresponding yy-values:

    • For x=0x = 0: k(0)=02+6(0)8=8k(0) = -0^2 + 6(0) - 8 = -8 So, one point on the graph is (0,8)(0, -8).

    • For x=1x = 1: k(1)=(1)2+6(1)8=1+68=3k(1) = -(1)^2 + 6(1) - 8 = -1 + 6 - 8 = -3 So, another point on the graph is (1,3)(1, -3).

Conclusion:

The two points on the graph of the parabola k(x)=x2+6x8k(x) = -x^2 + 6x - 8, other than the vertex and the xx-intercepts, are:

  • (0,8)(0, -8)
  • (1,3)(1, -3)

Would you like further clarification, or do you have any additional questions?

Related Questions:

  1. How do you find the yy-intercept of a parabola?
  2. What is the axis of symmetry for the parabola given by k(x)=x2+6x8k(x) = -x^2 + 6x - 8?
  3. How do you determine whether a parabola opens upwards or downwards?
  4. How would you complete the square to find the vertex form of k(x)k(x)?
  5. What is the significance of the discriminant in the context of finding the xx-intercepts?

Tip:

When working with parabolas, knowing the vertex and the direction it opens helps in quickly sketching its graph. The xx-intercepts provide additional points of intersection with the x-axis, making it easier to visualize.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Vertex of a Parabola
X-intercepts
Function Evaluation

Formulas

Quadratic formula

Theorems

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Suitable Grade Level

Grades 9-10