You can put this solution on YOUR website! Once you know how to multiply square roots, using FOIL on expressions with square roots in them is fairly easy.
The important thing to know when multiplying square roots is the basic property of all types of roots:
Some examples:
If there are coefficients in front of the square roots, then it's not much harder. You just use the Commutative and Associative properties of Multiplication to reorder and regroup so that you just multiply the coefficients and the square roots separately. An example:
Using the Commutative Property we can rearrange the order so the the coefficients are together and the square roots are together:
Then the Associative Property lets us group things as we choose:
Now we just multiply within each group:
Once you get the idea, you will probably be able to go straight from
to
Except for simplifying square roots (which is a whole other lesson), this is all you really need to know to use FOIL on expressions with square roots. For example:
Using FOIL on this:
which simplifies to:
(