Multiplying out two factors can be a little tricky. The FOIL mnemonic is a quick method when you have two terms in each factor, such as in:
(a + b)(a + b)
FOIL stands for:
- Firsts,
- Outer,
- Inner,
- Lasts.
It applies to the multiplication of the binomial cube.
Another way of showing the process — step by step — would be like this:
After FOILing you combine the similar terms: