MORE ON DIVISION OF RADICAL EXPRESSIONS
Rationalizing Denominators
Sometimes in mathematics it is useful to find an equivalent expression
without a radical in the denominator. This provides a standard notation for
expressing results. The procedure for finding such an expression is called
rationalizing the denominator.We carry this out by multiplying by 1.
Rationalizing When There Are Two Terms
Certain pairs of expressions containing square roots, such as c – 
, c + , and , 
– , + , are called conjugates. The product of such a pair of conjugates has no radicals in it.
Thus when we wish to rationalize a denominator that has two terms and one
or more of them involves a square-root radical, we multiply by 1 using the
conjugate of the denominator to write a symbol for 1.