Learn on PengiYoshiwara Elementary AlgebraChapter 5: Exponents and Roots

Lesson 4: Products of Binomials

New Concept This lesson teaches you how to multiply binomials. You'll learn to distribute each term from the first binomial to every term in the second. This process can be visualized using an area model, resulting in an expanded polynomial.

Section 1

πŸ“˜ Products of Binomials

New Concept

This lesson teaches you how to multiply binomials. You'll learn to distribute each term from the first binomial to every term in the second. This process can be visualized using an area model, resulting in an expanded polynomial.

What’s next

Soon, you'll use our interactive tools to see how the area model works. Then, you'll master the process with a series of practice cards.

Section 2

Products of variables

Property

The commutative and associative properties tell us that we can multiply the factors of a product in any order. To simplify a product like (3b)(4b)(3b)(4b), we can rearrange and group the factors:

(3b)(4b)=(3β‹…4)β‹…(bβ‹…b)=12b2(3b)(4b) = (3 \cdot 4) \cdot (b \cdot b) = 12b^2

Examples

  • To simplify (6a)(βˆ’4a)(6a)(-4a), we multiply the coefficients and the variables separately: (6)(βˆ’4)β‹…(a)(a)=βˆ’24a2(6)(-4) \cdot (a)(a) = -24a^2.
  • To simplify (3x)3(3x)^3, we multiply three copies of the expression: (3x)(3x)(3x)=(3β‹…3β‹…3)β‹…(xβ‹…xβ‹…x)=27x3(3x)(3x)(3x) = (3 \cdot 3 \cdot 3) \cdot (x \cdot x \cdot x) = 27x^3.

Section 3

Adding versus multiplying terms

Property

When we add like terms, we do not change the variable in the terms; we combine the coefficients. For example:

3a+2a=5a3a + 2a = 5a
When we multiply expressions, we multiply the coefficients and we multiply the variables:
3a(2a)=3(2)β‹…aβ‹…a=6a23a(2a) = 3(2) \cdot a \cdot a = 6a^2

Examples

  • Adding: 8x+3x=11x8x + 3x = 11x. Multiplying: (8x)(3x)=24x2(8x)(3x) = 24x^2.
  • Adding: 10y2+5y2=15y210y^2 + 5y^2 = 15y^2. Multiplying: (10y2)(5y2)=50y4(10y^2)(5y^2) = 50y^4.

Section 4

Using the distributive law

Property

The distributive law states that for any numbers aa, bb, and cc:

a(b+c)=ab+aca(b + c) = ab + ac
This means you can 'distribute' the multiplication to each term inside a set of parentheses.

Examples

  • To find the product 6(x+4)6(x+4), we distribute the 6 to both terms inside: 6(x)+6(4)=6x+246(x) + 6(4) = 6x + 24.
  • For 5a(3aβˆ’2)5a(3a-2), we distribute the 5a5a: 5a(3a)βˆ’5a(2)=15a2βˆ’10a5a(3a) - 5a(2) = 15a^2 - 10a.

Section 5

Types of algebraic expressions

Property

β€’ An algebraic expression with only one term, such as 2x42x^4, is called a monomial.
β€’ An expression with two terms, such as x2βˆ’16x^2 - 16, is called a binomial.
β€’ An expression with three terms is a trinomial.

Examples

  • A monomial has one term, like 8x38x^3 or βˆ’12-12.
  • A binomial has two terms, like 5xβˆ’95x - 9 or a2+b2a^2 + b^2.

Section 6

Multiplying binomials

Property

To multiply two binomials, multiply each term of the first binomial by each term of the second binomial. The acronym FOIL helps organize the four products:

  1. First terms
  2. Outer terms
  3. Inner terms
  4. Last terms
(xβˆ’4)(x+6)=x2+6xβˆ’4xβˆ’24=x2+2xβˆ’24(x-4)(x+6) = x^2 + 6x - 4x - 24 = x^2 + 2x - 24

Examples

  • Using FOIL for (x+2)(x+7)(x+2)(x+7): x2x^2 (F) +7x+ 7x (O) +2x+ 2x (I) +14+ 14 (L), which simplifies to x2+9x+14x^2 + 9x + 14.
  • For (3yβˆ’2)(y+5)(3y-2)(y+5): 3y23y^2 (F) +15y+ 15y (O) βˆ’2y- 2y (I) βˆ’10- 10 (L), which simplifies to 3y2+13yβˆ’103y^2 + 13y - 10.

Book overview

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Chapter 5: Exponents and Roots

  1. Lesson 1

    Lesson 1: Exponents

  2. Lesson 2

    Lesson 2: Square Roots and Cube Roots

  3. Lesson 3

    Lesson 3: Using Formulas

  4. Lesson 4Current

    Lesson 4: Products of Binomials

  5. Lesson 5

    Lesson 5.5: Chapter Summary and Review

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

πŸ“˜ Products of Binomials

New Concept

This lesson teaches you how to multiply binomials. You'll learn to distribute each term from the first binomial to every term in the second. This process can be visualized using an area model, resulting in an expanded polynomial.

What’s next

Soon, you'll use our interactive tools to see how the area model works. Then, you'll master the process with a series of practice cards.

Section 2

Products of variables

Property

The commutative and associative properties tell us that we can multiply the factors of a product in any order. To simplify a product like (3b)(4b)(3b)(4b), we can rearrange and group the factors:

(3b)(4b)=(3β‹…4)β‹…(bβ‹…b)=12b2(3b)(4b) = (3 \cdot 4) \cdot (b \cdot b) = 12b^2

Examples

  • To simplify (6a)(βˆ’4a)(6a)(-4a), we multiply the coefficients and the variables separately: (6)(βˆ’4)β‹…(a)(a)=βˆ’24a2(6)(-4) \cdot (a)(a) = -24a^2.
  • To simplify (3x)3(3x)^3, we multiply three copies of the expression: (3x)(3x)(3x)=(3β‹…3β‹…3)β‹…(xβ‹…xβ‹…x)=27x3(3x)(3x)(3x) = (3 \cdot 3 \cdot 3) \cdot (x \cdot x \cdot x) = 27x^3.

Section 3

Adding versus multiplying terms

Property

When we add like terms, we do not change the variable in the terms; we combine the coefficients. For example:

3a+2a=5a3a + 2a = 5a
When we multiply expressions, we multiply the coefficients and we multiply the variables:
3a(2a)=3(2)β‹…aβ‹…a=6a23a(2a) = 3(2) \cdot a \cdot a = 6a^2

Examples

  • Adding: 8x+3x=11x8x + 3x = 11x. Multiplying: (8x)(3x)=24x2(8x)(3x) = 24x^2.
  • Adding: 10y2+5y2=15y210y^2 + 5y^2 = 15y^2. Multiplying: (10y2)(5y2)=50y4(10y^2)(5y^2) = 50y^4.

Section 4

Using the distributive law

Property

The distributive law states that for any numbers aa, bb, and cc:

a(b+c)=ab+aca(b + c) = ab + ac
This means you can 'distribute' the multiplication to each term inside a set of parentheses.

Examples

  • To find the product 6(x+4)6(x+4), we distribute the 6 to both terms inside: 6(x)+6(4)=6x+246(x) + 6(4) = 6x + 24.
  • For 5a(3aβˆ’2)5a(3a-2), we distribute the 5a5a: 5a(3a)βˆ’5a(2)=15a2βˆ’10a5a(3a) - 5a(2) = 15a^2 - 10a.

Section 5

Types of algebraic expressions

Property

β€’ An algebraic expression with only one term, such as 2x42x^4, is called a monomial.
β€’ An expression with two terms, such as x2βˆ’16x^2 - 16, is called a binomial.
β€’ An expression with three terms is a trinomial.

Examples

  • A monomial has one term, like 8x38x^3 or βˆ’12-12.
  • A binomial has two terms, like 5xβˆ’95x - 9 or a2+b2a^2 + b^2.

Section 6

Multiplying binomials

Property

To multiply two binomials, multiply each term of the first binomial by each term of the second binomial. The acronym FOIL helps organize the four products:

  1. First terms
  2. Outer terms
  3. Inner terms
  4. Last terms
(xβˆ’4)(x+6)=x2+6xβˆ’4xβˆ’24=x2+2xβˆ’24(x-4)(x+6) = x^2 + 6x - 4x - 24 = x^2 + 2x - 24

Examples

  • Using FOIL for (x+2)(x+7)(x+2)(x+7): x2x^2 (F) +7x+ 7x (O) +2x+ 2x (I) +14+ 14 (L), which simplifies to x2+9x+14x^2 + 9x + 14.
  • For (3yβˆ’2)(y+5)(3y-2)(y+5): 3y23y^2 (F) +15y+ 15y (O) βˆ’2y- 2y (I) βˆ’10- 10 (L), which simplifies to 3y2+13yβˆ’103y^2 + 13y - 10.

Book overview

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

Continue this chapter

Chapter 5: Exponents and Roots

  1. Lesson 1

    Lesson 1: Exponents

  2. Lesson 2

    Lesson 2: Square Roots and Cube Roots

  3. Lesson 3

    Lesson 3: Using Formulas

  4. Lesson 4Current

    Lesson 4: Products of Binomials

  5. Lesson 5

    Lesson 5.5: Chapter Summary and Review