Math Problem Statement

Let f(x) = -(x + 1)^2 + 9. Use what you know about the shape of quadratic functions and their transformations to find the zeros of f(x).

Solution

The given quadratic function is:

f(x)=(x+1)2+9f(x) = - (x + 1)^2 + 9

We are asked to find the zeros (roots) of this function using knowledge of quadratic shapes and transformations.

Steps to find the zeros:

  1. Set f(x)=0f(x) = 0 to find the points where the function crosses the x-axis: (x+1)2+9=0- (x + 1)^2 + 9 = 0
  2. Isolate the squared term: (x+1)2=9- (x + 1)^2 = -9 Dividing both sides by 1-1: (x+1)2=9(x + 1)^2 = 9
  3. Take the square root of both sides: x+1=±3x + 1 = \pm 3
  4. Solve for xx: x+1=3orx+1=3x + 1 = 3 \quad \text{or} \quad x + 1 = -3 x=2orx=4x = 2 \quad \text{or} \quad x = -4

Zeros of the function:

The zeros of the function are x=2x = 2 and x=4x = -4.

Explanation of the graph:

  • The quadratic function is written in vertex form f(x)=a(xh)2+kf(x) = a(x-h)^2 + k, where the vertex is at (h,k)(h, k).
  • Here, a=1a = -1, meaning the parabola opens downward, and the vertex is at (1,9)(-1, 9).
  • Since the parabola opens downward and the zeros are x=2x = 2 and x=4x = -4, the graph touches the x-axis at these points.

Would you like further details on this, or do you have any questions?

Here are 5 related questions to expand on this:

  1. How does the value of aa in a quadratic equation affect the direction of the parabola?
  2. What is the significance of the vertex in the graph of a quadratic function?
  3. How do you determine the axis of symmetry for a quadratic function?
  4. How can you find the maximum or minimum value of a quadratic function?
  5. How do transformations (shifts and stretches) affect the graph of a quadratic equation?

Tip: The discriminant of a quadratic equation can help you quickly determine whether there are real, repeated, or no real solutions.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Transformations
Zeros of Functions

Formulas

f(x) = a(x-h)^2 + k
Solving quadratic equations by factoring or using square roots

Theorems

Zero Product Property
Vertex Form of a Quadratic Equation

Suitable Grade Level

Grades 9-10