Learn on PengienVision, Algebra 2Chapter 3: Polynomial Functions

Lesson 2: Adding, Subtracting, and Multiplying Polynomials

In this Grade 11 enVision Algebra 2 lesson, students learn how to add, subtract, and multiply polynomials by applying the Commutative, Associative, and Distributive Properties to group and combine like terms. The lesson covers operations with both single- and multi-variable polynomials, introduces the concept of closure under polynomial addition and subtraction, and shows how polynomial multiplication can model real-world problems such as maximizing profit using a quadratic function.

Section 1

Add and Subtract Polynomials

Property

To add or subtract polynomials, combine like terms. Like terms are monomials that have the same variables with the same exponents. The Commutative Property allows rearranging terms to group like terms together. When subtracting polynomials, be careful to distribute the negative sign to every term in the polynomial being subtracted.

Examples

  • To find the sum: (3x2+5x2)+(x22x+7)=(3x2+x2)+(5x2x)+(2+7)=4x2+3x+5(3x^2 + 5x - 2) + (x^2 - 2x + 7) = (3x^2 + x^2) + (5x - 2x) + (-2 + 7) = 4x^2 + 3x + 5.
  • To find the difference: (8a24a+1)(3a2a5)=8a24a+13a2+a+5=5a23a+6(8a^2 - 4a + 1) - (3a^2 - a - 5) = 8a^2 - 4a + 1 - 3a^2 + a + 5 = 5a^2 - 3a + 6.

Section 2

Products of polynomials

Property

To find the product of two polynomials, multiply each term of the first polynomial by each term of the second polynomial, then combine any like terms.

If a product contains a monomial factor, it is a good idea to multiply the polynomial factors together first, and save the monomial factor for last.

Examples

  • To multiply (x+5)(2x2x3)(x+5)(2x^2-x-3), we distribute term by term: x(2x2x3)+5(2x2x3)=2x3x23x+10x25x15=2x3+9x28x15x(2x^2-x-3) + 5(2x^2-x-3) = 2x^3-x^2-3x+10x^2-5x-15 = 2x^3+9x^2-8x-15.

Book overview

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Chapter 3: Polynomial Functions

  1. Lesson 1

    Lesson 1: Graphing Polynomial Functions

  2. Lesson 2Current

    Lesson 2: Adding, Subtracting, and Multiplying Polynomials

  3. Lesson 3

    Lesson 3: Polynomial Identities

  4. Lesson 4

    Lesson 4: Dividing Polynomials

  5. Lesson 5

    Lesson 5: Zeros of Polynomial Functions

  6. Lesson 6

    Lesson 6: Theorems About Roots of Polynomial Equations

  7. Lesson 7

    Lesson 7: Transformations of Polynomial Functions

Lesson overview

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Section 1

Add and Subtract Polynomials

Property

To add or subtract polynomials, combine like terms. Like terms are monomials that have the same variables with the same exponents. The Commutative Property allows rearranging terms to group like terms together. When subtracting polynomials, be careful to distribute the negative sign to every term in the polynomial being subtracted.

Examples

  • To find the sum: (3x2+5x2)+(x22x+7)=(3x2+x2)+(5x2x)+(2+7)=4x2+3x+5(3x^2 + 5x - 2) + (x^2 - 2x + 7) = (3x^2 + x^2) + (5x - 2x) + (-2 + 7) = 4x^2 + 3x + 5.
  • To find the difference: (8a24a+1)(3a2a5)=8a24a+13a2+a+5=5a23a+6(8a^2 - 4a + 1) - (3a^2 - a - 5) = 8a^2 - 4a + 1 - 3a^2 + a + 5 = 5a^2 - 3a + 6.

Section 2

Products of polynomials

Property

To find the product of two polynomials, multiply each term of the first polynomial by each term of the second polynomial, then combine any like terms.

If a product contains a monomial factor, it is a good idea to multiply the polynomial factors together first, and save the monomial factor for last.

Examples

  • To multiply (x+5)(2x2x3)(x+5)(2x^2-x-3), we distribute term by term: x(2x2x3)+5(2x2x3)=2x3x23x+10x25x15=2x3+9x28x15x(2x^2-x-3) + 5(2x^2-x-3) = 2x^3-x^2-3x+10x^2-5x-15 = 2x^3+9x^2-8x-15.

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 3: Polynomial Functions

  1. Lesson 1

    Lesson 1: Graphing Polynomial Functions

  2. Lesson 2Current

    Lesson 2: Adding, Subtracting, and Multiplying Polynomials

  3. Lesson 3

    Lesson 3: Polynomial Identities

  4. Lesson 4

    Lesson 4: Dividing Polynomials

  5. Lesson 5

    Lesson 5: Zeros of Polynomial Functions

  6. Lesson 6

    Lesson 6: Theorems About Roots of Polynomial Equations

  7. Lesson 7

    Lesson 7: Transformations of Polynomial Functions