Have you tried using factors of 18 under the square root sign?
okay, i seem to be pretty cool with the basics of rationalizing surds, just started doing a level maths, is going okay.
three questions, though, i keep trying to do and can't see where i'm going wrong, here they are.
don't know how to do the symbols so will just write it
square root of 6,
square root of six, plus square root of 3
i get 6 minus square root of 18,
however, the book says ....
2 minus square root of 2,....
i really can't see how they got this, hopefully if its explained, i'll be able to do the other two.