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[Kon-Tiki]

Found what they did in both. Seems that they did this:
9-x = (sqrt(x)+3)(-sqrt(x)+3)
And x-9 = (sqrt(x)+3)(sqrt(x)-3)
So they can scratch (sqrt(x)+3), leaving
(-sqrt(x)+3) <blablabla> / (sqrt(x)-3).
Then they put the top - outside of the brackets, giving this:
-(sqrt(x)-3) <blablabla> / (sqrt(x)-3)
You can now scratch (sqrt(x)-3), leaving:
-<blablabla>.
In the 5th exercise, it ends up beautifully in -6. In the next-to-last one, it ends up in
|x-4|?
I haven't fully figured out why they tossed one out in front, so that it looks like
(x-4)|x-4|

Thanks goes to Pogo on another forum for pointing the sqrt(x) thingy out.