Math Problem Statement

For the polynomial function below: (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 end behavior. The function is f(x) = (x - 2)^2(x + 9)^3.

Solution

Let’s analyze the given polynomial function step by step.

Given Function:

f(x)=(x2)2(x+9)3f(x) = (x - 2)^2 (x + 9)^3


(a) List each real zero and its multiplicity:

The zeros of a polynomial are the values of xx that make f(x)=0f(x) = 0.

  1. From the factor (x2)2(x - 2)^2, x=2x = 2 is a zero with multiplicity 22.
  2. From the factor (x+9)3(x + 9)^3, x=9x = -9 is a zero with multiplicity 33.

Zeros and their multiplicities:

  • x=2x = 2, multiplicity 22
  • x=9x = -9, multiplicity 33

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

The behavior at each intercept is determined by the multiplicity:

  1. Multiplicity 2 (even): The graph touches the x-axis at x=2x = 2 but does not cross it.
  2. Multiplicity 3 (odd): The graph crosses the x-axis at x=9x = -9.

Summary:

  • At x=2x = 2, the graph touches the x-axis.
  • At x=9x = -9, the graph crosses the x-axis.

(c) Determine the end behavior:

The end behavior of a polynomial is determined by the degree and the leading term.

  1. Degree of the polynomial: Degree=2(from\text{Degree} = 2 (from (x - 2)^2)+3(from) + 3 (from (x + 9)^3)=5) = 5

    The degree is odd.

  2. Leading coefficient: The product of the leading terms in (x2)2(x - 2)^2 and (x+9)3(x + 9)^3 is positive: (+1)(+1)5=+1(+1)(+1)^5 = +1

  3. End behavior for odd-degree polynomials with a positive leading coefficient:

    • As xx \to -\infty, f(x)f(x) \to -\infty (falls to the left).
    • As x+x \to +\infty, f(x)+f(x) \to +\infty (rises to the right).

Answer for end behavior: B. Falls left and rises right.


Final Answer Summary:

(a) Real zeros:

  • x=2x = 2, multiplicity 2
  • x=9x = -9, multiplicity 3

(b) Behavior at intercepts:

  • Touches the x-axis at x=2x = 2.
  • Crosses the x-axis at x=9x = -9.

(c) End behavior:

  • Falls left and rises right (B).

Do you have further questions or would you like a detailed graph analysis? Here are 5 related questions:

  1. How can you confirm the behavior of a graph at a zero using calculus (e.g., derivatives)?
  2. Why does even multiplicity result in touching but odd multiplicity results in crossing the x-axis?
  3. How do you determine leading coefficients from factored forms?
  4. What changes in end behavior if the leading coefficient is negative?
  5. How would adding another factor (e.g., (x+5)2(x + 5)^2) affect the end behavior?

Tip: Always verify graph behaviors by analyzing the polynomial's degree, leading coefficient, and multiplicities!

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Math Problem Analysis

Mathematical Concepts

Polynomial functions
Zeros of a polynomial
End behavior of polynomials

Formulas

Multiplicity: Behavior of the graph at each zero
Degree of polynomial: Sum of multiplicities
Leading term test for end behavior

Theorems

Behavior at zeros based on multiplicity
End behavior based on degree and leading coefficient

Suitable Grade Level

Grades 10-12