12 over 6 minus √13



Form the conjugate of the two term denominator
by the rule: A+B and A-B are conjugates of each
other.

So the conjugate of  is .

Then put the conjugate over itself, ,
which equals 1, and since it equals 1, we can multiply
 by it without changing its value.





FOIL out the bottom:











Either of the last two forms.

Edwin