Math Problem Statement

For the polynomial function f(x) = (x - 7)^3 (x + 9)^2, answer the following questions: (a) List each real zero and its multiplicity. (b) Determine whether the graph crosses or touches the x-axis at each x-intercept. (c) Determine the maximum number of turning points on the graph. (d) Determine the end behavior; that is, find the power function that the graph of f resembles for large values of |x|.

Solution

Let's analyze the polynomial function f(x)=(x7)3(x+9)2f(x) = (x - 7)^3 (x + 9)^2 step by step to answer the questions.

Given Information:

  1. Polynomial Function: f(x)=(x7)3(x+9)2f(x) = (x - 7)^3 (x + 9)^2

    This polynomial has two factors: (x7)3(x - 7)^3 and (x+9)2(x + 9)^2.

Part (a): List each real zero and its multiplicity.

  • The zeros of the function are values of xx that make each factor zero.
  • Zero at x=7x = 7: From the factor (x7)3(x - 7)^3, with multiplicity 3.
  • Zero at x=9x = -9: From the factor (x+9)2(x + 9)^2, with multiplicity 2.

Answer: The smallest zero is 9-9 with multiplicity 22, and the largest zero is 77 with multiplicity 33.

Part (b): Determine whether the graph crosses or touches the x-axis at each x-intercept.

  • For x = -9 (multiplicity 2), since it is an even multiplicity, the graph will touch the x-axis at this point.
  • For x = 7 (multiplicity 3), since it is an odd multiplicity, the graph will cross the x-axis at this point.

Answer: The graph touches the x-axis at x=9x = -9 and crosses the x-axis at x=7x = 7.

Part (c): Determine the maximum number of turning points on the graph.

  • The degree of f(x)f(x) can be found by adding the multiplicities: 3+2=53 + 2 = 5.
  • A polynomial of degree nn has at most n1n - 1 turning points.
  • Since the degree here is 5, the maximum number of turning points is 51=45 - 1 = 4.

Answer: The maximum number of turning points is 44.

Part (d): Determine the end behavior of f(x)f(x).

  • The highest degree term in f(x)=(x7)3(x+9)2f(x) = (x - 7)^3 (x + 9)^2 is x5x^5 (from expanding (x7)3(x+9)2(x - 7)^3 (x + 9)^2 and taking the highest power).
  • The term x5x^5 determines the end behavior, which is similar to y=x5y = x^5.
  • Since x5x^5 has an odd degree and a positive leading coefficient, as x+x \to +\infty, f(x)+f(x) \to +\infty; and as xx \to -\infty, f(x)f(x) \to -\infty.

Answer: The graph of f(x)f(x) resembles the power function y=x5y = x^5 for large values of x|x|.

If you need further explanation on any part or have specific questions, feel free to ask!


Related Practice Questions

  1. How do you determine the multiplicity of each zero in a polynomial?
  2. What is the difference in graph behavior between even and odd multiplicities at x-intercepts?
  3. How does the degree of a polynomial relate to its end behavior?
  4. How would the graph change if the polynomial had a factor with multiplicity 4 instead?
  5. How do turning points relate to the maximum number of x-intercepts in a polynomial?

Tip

For end behavior, focus on the highest degree term in the polynomial, as it dictates the behavior as xx \to \infty or xx \to -\infty.

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Math Problem Analysis

Mathematical Concepts

Polynomial Functions
Zeros of Polynomials
Multiplicity
Graph Behavior
End Behavior
Turning Points

Formulas

Multiplicity rules
Polynomial degree and turning points
End behavior analysis based on leading term

Theorems

Fundamental Theorem of Algebra

Suitable Grade Level

High School