In your initial discussion post, answer the following questions:

1. Given [tex]g(x)=(x-3)(x+2)(x+3)[/tex], describe the characteristics of the equation and then discuss a strategy for expanding this polynomial function. Are there any key features of the expanded polynomial you might be able to predict or identify?

2. For the polynomial equation [tex]x^3-4x^2=0[/tex], why does the related graph display only 2 x-intercepts rather than 3?

3. Do you think a cubic equation can be created such that the related function would have 4 x-intercepts? Explain your reasoning.

4. The Zero Product Property states that the product of factors is zero if and only if one or more of the factors are equal to zero. How does this support the relationship you have found?

5. What is the relationship between the degree of a polynomial, the number of roots it has, and the number of factors it has?



Answer :

Sure! Let's discuss the questions step-by-step:

### Characteristics of [tex]\(g(x) = (x-3)(x+2)(x+3)\)[/tex] and Expansion Strategy

1. Characteristics and Expansion:
The given polynomial [tex]\(g(x) = (x-3)(x+2)(x+3)\)[/tex] is a cubic polynomial because it is the product of three linear factors. This means the highest power of [tex]\(x\)[/tex] will be [tex]\(x^3\)[/tex]. To expand this polynomial, we can multiply the factors step by step.

[tex]\[ (x-3)(x+2)(x+3) \][/tex]

Let's first expand the product [tex]\((x+2)(x+3)\)[/tex]:

[tex]\[ (x+2)(x+3) = x^2 + 5x + 6 \][/tex]

Now, we multiply this result by the remaining factor [tex]\((x-3)\)[/tex]:

[tex]\[ (x-3)(x^2 + 5x + 6) = x(x^2 + 5x + 6) - 3(x^2 + 5x + 6) \][/tex]

Distributing [tex]\(x\)[/tex] and [tex]\(-3\)[/tex] respectively:

[tex]\[ = x^3 + 5x^2 + 6x - 3x^2 - 15x - 18 \][/tex]

Combining like terms, we get:

[tex]\[ = x^3 + 2x^2 - 9x - 18 \][/tex]

So, the expanded form of [tex]\(g(x)\)[/tex] is [tex]\(x^3 + 2x^2 - 9x - 18\)[/tex].

Key Features:
- The highest degree term is [tex]\(x^3\)[/tex], which confirms it is a cubic polynomial.
- The polynomial has three roots: [tex]\(x = 3\)[/tex], [tex]\(x = -2\)[/tex], and [tex]\(x = -3\)[/tex].

### Intercepts of the Polynomial [tex]\(x^3 - 4x^2 = 0\)[/tex]:

2. Intercepts of [tex]\(x^3 - 4x^2 = 0\)[/tex]:
To find the intercepts, we set the equation to zero and solve for [tex]\(x\)[/tex]:

[tex]\[ x^3 - 4x^2 = 0 \implies x^2(x - 4) = 0 \][/tex]

Using the Zero Product Property:

[tex]\[ x^2 = 0 \implies x = 0 \quad \text{(double root)} \][/tex]
[tex]\[ x - 4 = 0 \implies x = 4 \][/tex]

Hence, the roots are [tex]\(x = 0\)[/tex] (with multiplicity 2) and [tex]\(x = 4\)[/tex]. Although a cubic polynomial can have up to three x-intercepts, in this case, [tex]\(x = 0\)[/tex] only counts as one intercept on the graph, even though its multiplicity is 2.

### Can a Cubic Equation Have Four X-Intercepts?

3. Four X-Intercepts in a Cubic Equation:
No, a cubic equation cannot have four x-intercepts. The maximum number of x-intercepts a cubic polynomial can have is three because it is a polynomial of degree 3 and the Fundamental Theorem of Algebra states that a polynomial of degree [tex]\(n\)[/tex] can have at most [tex]\(n\)[/tex] roots (including multiplicities).

### Zero Product Property and Polynomial Roots

4. Zero Product Property:
The Zero Product Property states that if a product of factors equals zero, at least one of the factors must be zero. This property supports the determination of roots in polynomials. When we factored [tex]\(x^3 - 4x^2\)[/tex] into [tex]\(x^2(x-4) = 0\)[/tex], applying this property directly allowed us to find the roots ([tex]\(x = 0\)[/tex] and [tex]\(x = 4\)[/tex]).

### Degree, Roots, and Factors of a Polynomial

5. Relationship Between Degree, Roots, and Factors:
- The degree of a polynomial is the highest power of the variable in the polynomial.
- The number of roots (including multiplicity) of a polynomial is equal to its degree. Thus, a cubic polynomial (degree 3) has exactly 3 roots.
- A fully factored polynomial of degree [tex]\(n\)[/tex] will have [tex]\(n\)[/tex] linear factors corresponding to its [tex]\(n\)[/tex] roots. For example, [tex]\(x^3 - 4x^2\)[/tex] factors to [tex]\(x^2(x - 4)\)[/tex], which has 3 total linear factors when considering multiplicity (two factors of [tex]\(x\)[/tex] and one factor of [tex]\(x-4\)[/tex]).

In summary, the given cubic polynomial exemplifies the core properties of polynomial equations, including the method for expansion, the interpretation of roots and intercepts, and the fundamental principles that govern polynomial behavior.