Math Problem Statement

Find a polynomial function of degree 3 with real coefficients that has the given zeros.

minus1​,

2​,minus4

Solution

The polynomial function can be constructed using the given zeros. If a polynomial has zeros x=1x = -1, x=2x = 2, and x=4x = -4, we can express the polynomial in terms of its factors.

For each zero, there is a corresponding factor of the form (xr)(x - r), where rr is the zero.

  • For the zero x=1x = -1, the factor is (x+1)(x + 1).
  • For the zero x=2x = 2, the factor is (x2)(x - 2).
  • For the zero x=4x = -4, the factor is (x+4)(x + 4).

Thus, the polynomial is: f(x)=(x+1)(x2)(x+4)f(x) = (x + 1)(x - 2)(x + 4)

Now, let's expand the expression: f(x)=(x+1)(x2+4x2x8)=(x+1)(x2+2x8)f(x) = (x + 1)(x^2 + 4x - 2x - 8) = (x + 1)(x^2 + 2x - 8) f(x)=x(x2+2x8)+1(x2+2x8)f(x) = x(x^2 + 2x - 8) + 1(x^2 + 2x - 8) f(x)=x3+2x28x+x2+2x8f(x) = x^3 + 2x^2 - 8x + x^2 + 2x - 8 f(x)=x3+3x26x8f(x) = x^3 + 3x^2 - 6x - 8

Therefore, the polynomial function is: f(x)=x3+3x26x8f(x) = x^3 + 3x^2 - 6x - 8

Would you like any further details or explanations?

Here are 5 related questions:

  1. How can you find the degree of a polynomial from its factors?
  2. What does it mean for a polynomial to have real coefficients?
  3. How do you verify that the given zeros are correct for this polynomial?
  4. How do you factor polynomials of higher degrees?
  5. What is the relationship between the degree of a polynomial and its graph?

Tip: When multiplying polynomials, it's best to expand step by step to avoid mistakes.

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomial Functions
Roots of Polynomial Equations

Formulas

Polynomial from roots: f(x) = (x - r1)(x - r2)...(x - rn)

Theorems

Factor Theorem
Fundamental Theorem of Algebra

Suitable Grade Level

Grades 10-12