Math Problem Statement

Find a polynomial of degree 3 with real coefficients and zeros of -3, -1, and 4, for which f(-2) = 24.

Solution

Let's break down and solve the problem shown in the image.

Problem:

Find a polynomial of degree 3 with real coefficients and zeros of 3-3, 1-1, and 44, for which f(2)=24f(-2) = 24.

Step-by-Step Solution:

  1. Form the Polynomial: Since the zeros of the polynomial are 3-3, 1-1, and 44, the factors of the polynomial are: (x+3),(x+1),(x4)(x + 3), (x + 1), (x - 4) The general form of the polynomial is: f(x)=a(x+3)(x+1)(x4)f(x) = a(x + 3)(x + 1)(x - 4) where aa is a constant to be determined.

  2. Use the Condition f(2)=24f(-2) = 24: To find aa, we substitute x=2x = -2 into the polynomial and set it equal to 24: f(2)=a(2+3)(2+1)(24)=24f(-2) = a(-2 + 3)(-2 + 1)(-2 - 4) = 24 Simplifying each factor: f(2)=a(1)(1)(6)=24f(-2) = a(1)(-1)(-6) = 24 6a=24-6a = 24 Solving for aa: a=246=4a = \frac{24}{-6} = -4

  3. Write the Final Polynomial: Now that we know a=4a = -4, the polynomial is: f(x)=4(x+3)(x+1)(x4)f(x) = -4(x + 3)(x + 1)(x - 4)

  4. Expand the Polynomial (Optional): If you want to simplify the polynomial further, you can expand it: f(x)=4[(x+3)(x+1)(x4)]f(x) = -4[(x + 3)(x + 1)(x - 4)] First, expand (x+3)(x+1)(x + 3)(x + 1): (x+3)(x+1)=x2+4x+3(x + 3)(x + 1) = x^2 + 4x + 3 Now multiply this by (x4)(x - 4): (x2+4x+3)(x4)=x34x2+4x216x+3x12(x^2 + 4x + 3)(x - 4) = x^3 - 4x^2 + 4x^2 - 16x + 3x - 12 Simplify: =x313x12= x^3 - 13x - 12 Finally, multiply by 4-4: f(x)=4(x313x12)=4x3+52x+48f(x) = -4(x^3 - 13x - 12) = -4x^3 + 52x + 48 So the polynomial is: f(x)=4x3+52x+48f(x) = -4x^3 + 52x + 48

This is the polynomial you're looking for. Do you need further clarification on any step?


Related Questions:

  1. How do you find the roots of a cubic polynomial?
  2. What is the importance of the constant aa in defining a polynomial?
  3. Can the polynomial have complex roots if the coefficients are real?
  4. What methods can be used to factor a cubic polynomial directly?
  5. How does the transformation f(2)=24f(-2) = 24 affect the graph of the polynomial?

Tip:

When given roots, always form the polynomial using the corresponding factors and then adjust for any scaling conditions using additional information provided (like f(x)f(x) values).

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomials
Zeros of Polynomials

Formulas

f(x) = a(x + 3)(x + 1)(x - 4)
Substituting to find constant a
Expanding polynomials

Theorems

Factor Theorem

Suitable Grade Level

High School or College Algebra