How do you FOIL (x-10)(x+10)?

1 Answer
Mar 5, 2018

x^2-100

Explanation:

FOIL stands for First, Outside, Inside, Last

multiply the First terms
x*x=x^2

multiply the Outside terms
x*10=10x

multiply the Inside terms
-10*x=-10x

multiply the Last terms
-10*10=-100

add all of the answers together
x^2+10x-10x-100

combine like terms
x^2+color(red)(10x-10x)-100
=x^2-100