Learn on PengiSaxon Algebra 1Chapter 10: Systems and Problem Solving

Lesson 93: Dividing Polynomials

In this Grade 9 Saxon Algebra 1 lesson, students learn to divide polynomials by monomials, binomials, and using polynomial long division, including cases with remainders and zero coefficients. The lesson covers writing division problems as rational expressions, factoring to cancel common factors, and expressing non-zero remainders as rational expressions over the divisor. It is part of Chapter 10: Systems and Problem Solving.

Section 1

📘 Dividing Polynomials

New Concept

To divide a polynomial by a monomial, divide each term in the numerator by the denominator.

What’s next

Next, you’ll apply this concept by dividing polynomials by monomials and then use factoring and long division for more complex problems.

Section 2

Dividing a polynomial by a monomial

Property

To divide a polynomial by a monomial, divide each term in the numerator by the denominator.

a+bc=ac+bc \frac{a+b}{c} = \frac{a}{c} + \frac{b}{c}

Explanation

Think of the polynomial as a party-size sub sandwich and the monomial as your friends. To share it fairly, you cut each section (term) of the sandwich and give a piece to every friend. This way, every part of the polynomial gets divided equally!

Examples

  • (16x3+8x2+4x)÷4x=16x34x+8x24x+4x4x=4x2+2x+1 (16x^3 + 8x^2 + 4x) \div 4x = \frac{16x^3}{4x} + \frac{8x^2}{4x} + \frac{4x}{4x} = 4x^2 + 2x + 1
  • (9y4−15y2)÷3y2=9y43y2−15y23y2=3y2−5 (9y^4 - 15y^2) \div 3y^2 = \frac{9y^4}{3y^2} - \frac{15y^2}{3y^2} = 3y^2 - 5

Section 3

Dividing a polynomial by a binomial

Property

If possible, factor the numerator and denominator, then divide out any common factors to simplify the expression.

(x+a)(x+b)(x+a)=x+b \frac{(x+a)(x+b)}{(x+a)} = x+b

Explanation

This is the ultimate shortcut for division! It’s like finding matching socks in a messy drawer. Once you spot a matching factor on the top and bottom, you can cancel them out. What’s left over is your much tidier, simplified answer. Easy peasy!

Examples

  • (x2+8x+15)÷(x+3)=(x+5)(x+3)x+3=x+5 (x^2 + 8x + 15) \div (x+3) = \frac{(x+5)(x+3)}{x+3} = x+5
  • x2−6x+9x−3=(x−3)(x−3)x−3=x−3 \frac{x^2 - 6x + 9}{x-3} = \frac{(x-3)(x-3)}{x-3} = x-3

Section 4

Dividing a polynomial using long division

Property

Write the divisor and dividend in descending order before dividing. Use the same steps as numerical long division: divide, multiply, subtract, and bring down.

dividenddivisor=quotient+remainderdivisor \frac{\text{dividend}}{\text{divisor}} = \text{quotient} + \frac{\text{remainder}}{\text{divisor}}

Explanation

When factoring fails, long division is your trusty backup plan. Just like with regular numbers, you tackle the polynomial piece by piece. Line everything up neatly, and you'll solve even the trickiest division problems without breaking a sweat. It's old school but it always works!

Examples

  • (x2+7x+10)÷(x+2)=x+5 (x^2 + 7x + 10) \div (x+2) = x+5
  • (2x2+x−5)÷(x−2)=2x+5+5x−2 (2x^2 + x - 5) \div (x-2) = 2x + 5 + \frac{5}{x-2}

Book overview

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

Continue this chapter

Chapter 10: Systems and Problem Solving

  1. Lesson 1

    Lesson 91: Solving Absolute-Value Inequalities

  2. Lesson 2

    Lesson 92: Simplifying Complex Fractions

  3. Lesson 3Current

    Lesson 93: Dividing Polynomials

  4. Lesson 4

    Lesson 94: Solving Multi-Step Absolute-Value Equations

  5. Lesson 5

    Lesson 95: Combining Rational Expressions with Unlike Denominators

  6. Lesson 6

    Lesson 96: Graphing Quadratic Functions

  7. Lesson 7

    Lesson 97: Graphing Linear Inequalities

  8. Lesson 8

    Lesson 98: Solving Quadratic Equations by Factoring

  9. Lesson 9

    Lesson 99: Solving Rational Equations

  10. Lesson 10

    Lesson 100: Solving Quadratic Equations by Graphing

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

📘 Dividing Polynomials

New Concept

To divide a polynomial by a monomial, divide each term in the numerator by the denominator.

What’s next

Next, you’ll apply this concept by dividing polynomials by monomials and then use factoring and long division for more complex problems.

Section 2

Dividing a polynomial by a monomial

Property

To divide a polynomial by a monomial, divide each term in the numerator by the denominator.

a+bc=ac+bc \frac{a+b}{c} = \frac{a}{c} + \frac{b}{c}

Explanation

Think of the polynomial as a party-size sub sandwich and the monomial as your friends. To share it fairly, you cut each section (term) of the sandwich and give a piece to every friend. This way, every part of the polynomial gets divided equally!

Examples

  • (16x3+8x2+4x)÷4x=16x34x+8x24x+4x4x=4x2+2x+1 (16x^3 + 8x^2 + 4x) \div 4x = \frac{16x^3}{4x} + \frac{8x^2}{4x} + \frac{4x}{4x} = 4x^2 + 2x + 1
  • (9y4−15y2)÷3y2=9y43y2−15y23y2=3y2−5 (9y^4 - 15y^2) \div 3y^2 = \frac{9y^4}{3y^2} - \frac{15y^2}{3y^2} = 3y^2 - 5

Section 3

Dividing a polynomial by a binomial

Property

If possible, factor the numerator and denominator, then divide out any common factors to simplify the expression.

(x+a)(x+b)(x+a)=x+b \frac{(x+a)(x+b)}{(x+a)} = x+b

Explanation

This is the ultimate shortcut for division! It’s like finding matching socks in a messy drawer. Once you spot a matching factor on the top and bottom, you can cancel them out. What’s left over is your much tidier, simplified answer. Easy peasy!

Examples

  • (x2+8x+15)÷(x+3)=(x+5)(x+3)x+3=x+5 (x^2 + 8x + 15) \div (x+3) = \frac{(x+5)(x+3)}{x+3} = x+5
  • x2−6x+9x−3=(x−3)(x−3)x−3=x−3 \frac{x^2 - 6x + 9}{x-3} = \frac{(x-3)(x-3)}{x-3} = x-3

Section 4

Dividing a polynomial using long division

Property

Write the divisor and dividend in descending order before dividing. Use the same steps as numerical long division: divide, multiply, subtract, and bring down.

dividenddivisor=quotient+remainderdivisor \frac{\text{dividend}}{\text{divisor}} = \text{quotient} + \frac{\text{remainder}}{\text{divisor}}

Explanation

When factoring fails, long division is your trusty backup plan. Just like with regular numbers, you tackle the polynomial piece by piece. Line everything up neatly, and you'll solve even the trickiest division problems without breaking a sweat. It's old school but it always works!

Examples

  • (x2+7x+10)÷(x+2)=x+5 (x^2 + 7x + 10) \div (x+2) = x+5
  • (2x2+x−5)÷(x−2)=2x+5+5x−2 (2x^2 + x - 5) \div (x-2) = 2x + 5 + \frac{5}{x-2}

Book overview

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

Continue this chapter

Chapter 10: Systems and Problem Solving

  1. Lesson 1

    Lesson 91: Solving Absolute-Value Inequalities

  2. Lesson 2

    Lesson 92: Simplifying Complex Fractions

  3. Lesson 3Current

    Lesson 93: Dividing Polynomials

  4. Lesson 4

    Lesson 94: Solving Multi-Step Absolute-Value Equations

  5. Lesson 5

    Lesson 95: Combining Rational Expressions with Unlike Denominators

  6. Lesson 6

    Lesson 96: Graphing Quadratic Functions

  7. Lesson 7

    Lesson 97: Graphing Linear Inequalities

  8. Lesson 8

    Lesson 98: Solving Quadratic Equations by Factoring

  9. Lesson 9

    Lesson 99: Solving Rational Equations

  10. Lesson 10

    Lesson 100: Solving Quadratic Equations by Graphing