How To Multiply Binomials Using The FOIL Method

Marvel fans assemble for the ultimate holiday giveaway! Enter now for your chance to win.dummies logo Dummies AI Browse Book & Article Categories

Book & Article Categories

closeTechnologyAcademics & The ArtsHome, Auto, & HobbiesBody, Mind, & SpiritBusiness, Careers, & MoneyCollections

Collections

Explore all collectionscloseBYOB (Be Your Own Boss)Be a Rad DadCareer ShiftingContemplating the CosmosFor Those Seeking Peace of MindFor the Aspiring AficionadoFor the Budding Cannabis EnthusiastFor the College BoundFor the Exam-Season CrammerFor the Game Day PrepperCustom Solutionsdummies logo
  • Book & Article Categoriesforward arrow
  • Collectionsforward arrow
  • Custom Solutions
  • Dummies AI
  • forward arrowMain Menu
  • Book & Article Categories

  • Technology
  • Academics & The Arts
  • Home, Auto, & Hobbies
  • Body, Mind, & Spirit
  • Business, Careers, & Money
  • Dummies AI
  • forward arrowMain Menu
  • Book & Article Categories

  • Technology
  • Academics & The Arts
  • Home, Auto, & Hobbies
  • Body, Mind, & Spirit
  • Business, Careers, & Money
  • Dummies AI
  • forward arrowMain Menu
  • Collections

    Explore all collections
  • BYOB (Be Your Own Boss)
  • Be a Rad Dad
  • Career Shifting
  • Contemplating the Cosmos
  • For Those Seeking Peace of Mind
  • For the Aspiring Aficionado
  • For the Budding Cannabis Enthusiast
  • For the College Bound
  • For the Exam-Season Crammer
  • For the Game Day Prepper
  • Dummies AI
HomeAcademics & The Arts ArticlesMath ArticlesAlgebra ArticlesHow to Multiply Binomials Using the FOIL MethodByNo items found.Updated2016-03-26 21:47:08From the bookNo items found.Share
Download E-BookPersonal Finance For DummiesExplore BookAlgebra II All-in-One For Dummies Explore BookBuy NowBuy on AmazonBuy on WileySubscribe on PerlegoDownload E-BookPersonal Finance For DummiesExplore BookAlgebra II All-in-One For DummiesExplore BookBuy NowBuy on AmazonBuy on WileySubscribe on Perlego

The FOIL method lets you multiply two binomials in a particular order. You don't have to multiply binomials by following the FOIL order, but it does make the process easier. The letters in FOIL refer to two terms (one from each of two binomials) multiplied together in a certain order: First, Outer, Inner, and Last.

Example 1: (2x + 3)(3x – 1)

The following steps demonstrate how to use FOIL on this multiplication problem.

  1. Multiply the first term of each binomial together.

    image0.png
  2. Multiply the outer terms together.

    (2x)(–1) = –2x

  3. Multiply the inner terms together.

    (3)(3x) = 9x

  4. Multiply the last term of each expression together.

    (3)(–1) = –3

  5. List the four results of FOIL in order.

    image1.png
  6. Combine the like terms.

    image2.png

Example 2: (x – 3)(2x – 9)

See how the FOIL numbered steps work on a couple of negative terms.

  1. Multiply the first terms.

    image3.png
  2. Multiply the outer terms.

    (x)(–9) = –9x

  3. Multiply the inner terms.

    (–3)(2x) = –6x

  4. Multiply the last terms.

    (–3)(–9) = 27

  5. List the four results of FOIL in order.

    image4.png
  6. Combine the like terms.

    image5.png

Example 3: [x + (y – 4)][3x + (2y + 1)]

This example is a bit more complicated, but FOIL makes it much easier. The tasks are broken down into smaller, simpler steps, and then the results are combined.

  1. Multiply the first terms.

    image6.png
  2. Multiply the outer terms.

    (x)(2y + 1) = 2xy + x

  3. Multiply the inner terms.

    (y – 4)(3x) = 3xy – 12x

  4. Multiply the last terms.

    The last terms are also two binomials. You FOIL these binomials when you finish this series of FOIL steps.

    (y – 4)(2y + 1)

  5. List the four results of FOIL in order.

    image7.png
  6. Combine like terms.

    image8.png
  7. FOIL the product of two binomials from Step 4: (y – 4)(2y + 1).

    image9.png

    Multiply the outer terms: (y)(1) = y

    Multiply the inner terms: (–4)(2y) = –8y

    Multiply the last terms: (–4)(1) = –4

    image10.png
  8. Replace the two binomials multiplied together with this new result, and then rewrite the entire problem.

    image11.png

About This Article

This article is from the book: 

No items found.

About the book author:

No items found.

This article can be found in the category: 

AlgebraNo items found.Get a Subscription

Tag » What Is Foil In Math