In the previous example, we multiplied two radical expressions,
You may have been surprised that the result -22, does not contain a
Letâ€™s recall why that is so.
We used the FOIL method to multiply:
Letâ€™s look again at the original two radical expressions.
Such binomial radical expressions are called conjugates
Here are some other examples of conjugates:
When we multiply two conjugate radical expressions, the result is a
rational number. For this reason, conjugates are used to simplify certain
types of radical expressions.
by its conjugate.
|The conjugate of
|Use the FOIL method.
|The two middle terms are
opposites and add to zero.
||= 25 - 2