document.write( "Question 701522: Can you please explain foil for me? I've tried many times but I can't get the hang of it.
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Algebra.Com's Answer #432454 by Simnepi(216) $\"\"$ $\"About$

You can put this solution on YOUR website!
FOIL stands for
\n" ); document.write( "First, Outer,Inner, Last and is a great way of remembering how to expand two brackets with two terms in. for instance (a+b) and (c+d) where a,b,c and d represent algebraic terms.
\n" ); document.write( "(When using FOIL you also have to remember the rules for multiplying positive and negative numbers.)
\n" ); document.write( "So lets get back to the brackets
\n" ); document.write( "(a+b)(c+d)
\n" ); document.write( "Foil says multiply the First terms in the brackets
\n" ); document.write( "so multiplying a and c gives +ac
\n" ); document.write( "Then, multiply the Outer terms, those that are furthest from the middle of the bracket
\n" ); document.write( "so multiplying a and d gives +ad
\n" ); document.write( "Then multiply the Inner terms in each bracket, those that are closest together
\n" ); document.write( "so multiplying b and c gives +bc
\n" ); document.write( "Then,multiply the Last term in each bracket
\n" ); document.write( "so multiplying b and d gives +bd
\n" ); document.write( "putting all those terms together gives us
\n" ); document.write( "(a+b)(c+d)=ac+ad+bc+bd
\n" ); document.write( "Lets see if I can show you a couple useful things to help
\n" ); document.write( "If you have a bracket which is squared i.e.
\n" ); document.write( " $\"%28x%2By%29%5E2\"$
\n" ); document.write( "this is the same as (x+y)(x+y)
\n" ); document.write( "Using FOIL gives us terms
\n" ); document.write( " $\"x%5E2\"$ , +xy, +xy and $\"y%5E2\"$ i.e.
\n" ); document.write( " $\"x%5E2%2Bxy%2Bxy%2By%5E2\"$ simplifying this gives $\"x%5E2%2B2xy%2By%5E2\"$
\n" ); document.write( "so $\"%28x%2By%29%5E2=x%5E2%2B2xy%2By%5E2\"$
\n" ); document.write( "Let-s look at another but with negative signs i.e.
\n" ); document.write( " $\"x-y%29%5E2\"$
\n" ); document.write( "this is the same as (x-y)(x-y)This time remembering that
\n" ); document.write( "positive X negative = negative and
\n" ); document.write( "negative X negative = positive
\n" ); document.write( "using FOIL this time gives us terms
\n" ); document.write( " $\"x%5E2\"$ , -xy, -xy and + $\"y%5E2\"$ i.e.\r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2-xy=xy%2By%5E2\"$ simplifying this gives $\"x%5E2-2xy%2By%5E2\"$
\n" ); document.write( "so

(x-y)^2=x^2-2xy+y^2}}
\n" ); document.write( "Hope that helped.
\n" ); document.write( "The best thing is to practice a few for yourself! \n" ); document.write( "

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