1. Using a scale of 1 – 5 with 1 being “very uncomfortable” and 5 being “very comfortable,” briefly describe your level of comfort with factoring polynomials.
2. Provide an explanation as to why you gave the rating above.
3. Why is it important to consider the product rule for exponents when multiplying polynomials? Be sure to provide at least one example in your response.
Response focus
1. In your response, in addition to the standard requirement of noting what you have in common and where you differ with classmates, offer a suggestion as to how to improve your classmates’ comfort level with the topics we are studying this week.
Remember to review the academic expectations for your submission.
Submission reminders:
· Submit your initial discussion post by 11:59 pm ET on Wednesday. Respond to two of your classmates’ discussion posts, and reply to the responses you received by 11:59 pm ET on Sunday.
· Contribute a minimum of 200 words to the initial post.
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Module 3: Polynomials and Polynomial Functions II
Factoring
Factoring is the opposite of multiplying. To factor an expression means to write it as a product of other expressions.
A polynomial is a finite sum of terms in which all variables have whole number exponents and no variable appears in a denominator. A monomial is a polynomial with one term. A binomial is a polynomial with two terms. A trinomial is a polynomial with three terms.
The Greatest Common Factor ( GCF) is the product of the factors common to all terms in the polynomial.
Find the Greatest Common Factor:
To factor a monomial from a polynomial, we need to factor out the Greatest Common Factor from each term in the polynomial.
Examples:
A. 6x 21, the GCF is 3, then the factors of the polynomial are: 6x 21 = 3(2x 7)
B. 𝑥3𝑦2, 𝑥𝑦4, 𝑥5𝑦6, the highest power of x that is common to all three terms is x (𝑥1). The highest power of y that is common to all three terms is 𝑦2. Thus, the GCF of the three terms is 𝑥𝑦2.
Factor a Monomial from a Polynomial:
Steps:
1. Determine the GCF of all terms in the polynomial.
2. Write each term as the product of the GCF and another factor. 3) Use the distributive product to factor out the GCF.
Example:
Factor 15𝑥4 − 5𝑥3 25𝑥2
1. The GCF is 5𝑥2
2. Each term as the product of the GCF and another product: 5𝑥2 *3𝑥2 − 5𝑥2*𝑥 5𝑥2*5
3. Factor out the GCF: 5𝑥2(3𝑥2 − 𝑥 5)
Factor a Common Binomial Factor
Involves factoring a binomial as the GCF.
Example:
Factor 9x(2x-3) 7(2x-3) GCF: (2x-3) Factoring out the GCF: (2x-3)(9x 7)
Factor by Grouping
Involves factoring a polynomial that contains four terms. To factor by grouping, remove common factors from group of terms.
Example: Factor 𝑥3 2𝑥 − 5𝑥2 − 10
Steps
1. Determine if all four terms have a common factor. If so, factor out the GCF from each term.
2. Arrange the four terms into two groups of two terms each. Each group of two terms must have a GCF.
3. Factor the GCF from each group of two terms.
4. If the two terms formed in step c have a GCF, factor it out.
Note: In this example, there are no factors common to all four terms. Factor x from the first two terms and -5 from the last two term: 𝑥3 2𝑥−5𝑥2 −10 = 𝑥(𝑥2 2) − 5(𝑥2 2) = (𝑥2 2)(𝑥−5)
Factoring Trinomials
Factor Trinomials of the Form 𝑥2 𝑏𝑥 𝑐
Find two numbers (or factors) whose product is c and whose sum is b.
Example:
Factor 𝑥2 − 𝑥 − 12
a= 1 b = -1 c = -12
find two numbers whose product is -12 and whose sum is -1 (x 3) (x – 4)
Factor Trinomials of the Form 𝑎𝑥2 𝑏𝑥 𝑐
1. Find two numbers whose product is a.c and whose sum is b
2. Rewrite the middle term, bx, using the numbers found in step 1
3. Factor by grouping.
Example: Factor 2𝑥2 − 5𝑥 − 12
a = 2 b = -5 c = -12
Steps:
1. Find two numbers whose product is a.c and whose sum is b: 2(-12) = 24, sum = -5 The two numbers are -8 and 3
2. Rewrite the middle term, bx, using the numbers found in step 1: -5x, using -8x and 3x: -8x 3x
3. Factor by grouping:
A. 2𝑥2 − 8𝑥 3𝑥 − 12.
B. That gets: 2x(x -4) 3 (x – 4)
C. (x – 4) (2x 3)
Special Factoring Formulas
Factoring the difference of two squares:
𝑎2 − 𝑏2 = (𝑎 𝑏)(𝑎 − 𝑏)
Example:
Factor 𝑥2 − 16
𝑥2−16 = (𝑥)2−(4)2 = (𝑥 4)(𝑥−4)
Quadratic Equations
The formula −b±b2−4ac2a can be used to solve quadratic equations in the form of: 𝑎𝑥2 𝑏𝑥 𝑐
Example:
Solve 𝑥2 2𝑥 − 8
a= 1 b= 2 c = -8
𝑥 = −b±b2−4ac2a = −2±22−4(1)(−8)2(1) = −2±4 322
= −2±362 = −2±62 = 𝑥 = −2−62orx=−2 62
x=−4orx=2
References
Angel, A.,