# How do you multiply #(sqrt5- sqrt2)(sqrt5+sqrt2)#?

##### 2 Answers

So

#### Explanation:

using the difference of squares identity:

Alternatively use FOIL to pick pairs of terms to multiply and add together:

First:

Outside:

Inside:

Last:

F + O + I + L =

The answer is

#### Explanation:

You can use "FOIL" (First-Outside-Inside-Last) as follows:

After cancellation and use of the facts that

The reason "FOIL" works is because of abstract properties of numbers systems, such as the Distributive Property, which says that

This can be rearranged, by the Commutative Property, to

It's also worthwhile to memorize the difference of two squares factoring formula: