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## College Algebra

### Course: College Algebra>Unit 4

Lesson 1: Multiplying binomials

# Multiplying binomials

Sal expresses the product (3x+2)(5x-7) as 15x²-11x-14. Created by Sal Khan and Monterey Institute for Technology and Education.

## Want to join the conversation?

• This is the first time im hearing of FOIL. In school, they never made a mnemonic or abbr for it,they just teach you the distributive property and you apply it everywhere.
• Pay no mind to it then...It might confuse you at first, like it did to me.
• math is not my jam people
• Yeah, I understand that, ggallegos. But remember first off for things like this topic of multiplying binomials have more than one way of solving, so try each method to see what works for you. Second off, remember that you can use the calculator for some problems. They won't always allow calculators, but they help especially with doing something like 21 x 36 when you're dealing with large numbers. Hope this helps.
• Did the FOIL method really make sense? The FOIL method is very similar with the standard method that is used for multiplying binomial, Distributive Property of Multiplication. How does it makes sense?
Ex.
``(3x+2)(5x-7)For Standard Method(Distributive):(3x.5x)(3x.(-7))(2.5x)(2.(-7))For FOIL Method:F - (3x)(5x)O - (3x)(-7)I - (2)(5x)L - (2)(-7)``

What's the difference?
• "FOIL" is just a mnemonic. It helps some people to remember all the steps needed to multiply two binomials.
It "makes sense" because it's methodical and gives the right answer. What point are you trying to make?
• What are special products?
• Point of humor.... Im 45, and stopped this video as soon as you had the equation on the screen and forced myself to remember the FOIL concept from highschool. Took me a couple tries to get it right (forgot to square the first time), but at any rate, i thought it was funny to then finish the video and say we may not remember... I only remembered it as "outside first" and didn't remember the actual term "FOIL", but yea, made me chuckle! :-)
• When do you use the foil method?
• Ann,
You use the FOIL method when you are multiplying two binomials; that is multiplying two factors with two terms in each factor.
• I don't really understand FOIL,can somebody explain it again to me ? thanks
• "A technique for distributing two binomials. The letters FOIL stand for First, Outer, Inner, Last. First means multiply the terms which occur first in each binomial. Then Outer means multiply the outermost terms in the product."

http://www.mathwords.com/f/foil_method.htm
• I hated it when he said you might forget it when you are 34 or 35. because I am already 34 right now and studying algebra :(