Question 387167
<pre>
FOIL (or F.O.I.L.) is an acronym for "FIRSTS, "OUTERS", "INNERS", "LASTS".

When you have two parentheses multiplied with two terms in each,
like this:

(A + B)(C + D)

(<font color="red">A</font> + B)(<font color="red">C</font> + D)

<font color="red">A</font> and the <font color="red">C</font> are the FIRST terms in each parentheses

You multiply them together and in this case you get <font color="red">AC</font>

-------------------------------------------------


(<font color="red">A</font> + B)(C + <font color="red">D</font>)

The A and the D are the OUTER ones in each parentheses (the furthest apart)

You multiply them together and in this case you get <font color="red">AD</font>

-------------------------------------------------

(A + <font color="red">B</font>)(<font color="red">C</font> + D)

The B and the C are the INNER ones in each parentheses (the closest ones together)

You multiply them together and in this case you get <font color="red">BC</font>

-------------------------------------------------

(A + <font color="red">B</font>)(C + <font color="red">D</font>)

The B and the D are the LAST ones in each parentheses

You multiply them together and in this case you get <font color="red">BD</font>

-------------------------------------------------

So the sum of all four of them is F + O + I + L or

<font color="red">AC</font> + <font color="red">AD</font> + <font color="red">BC</font> + <font color="red">BD</font>

-------------------------------------------------

Edwin</pre>