Posted by charlotte.skinner@uc.edu (218.186.42.60) on January 12, 2003 at 00:30:45:
In Reply to: HELP!! Algebra Question posted by on January 11, 2003 at 01:47:34:
FOIL is an acronym for First, Outer, Inner, Last, and refers to the process of multiplying 2 binomials (algebraic expressions with exactly 2 terms).
Ex. To multiply (2x + 5)(x - 3), you need to multiply every possible combination (4 in all), and FOIL is a way to keep track of them. Find the products of the First, Outer, Inner and Last terms of each binomial, and add together.
First: (2x)(x)=2x^2
Outer: (2x)(-3)=-6x
Inner: (5)(x)=5x
Last: (5)(-3)=-15
Add the terms together = 2x^2-x-15.
Very often the Outer and Inner products are like terms and can be combined.