-6√63 - 9√28 + 2√14
Factor 63 as 9*7 and then as 3²·7, so 63 contains a perfect square factor
Factor 28 as 4*7 and then as 2²·7, so 28 contains a perfect square factor
Factor 14 as 2*7 but 14 does not contains a perfect square factor,
so we just leave it as 14
-6√3²·7 - 9√2²·7 + 2√14
We can take 3² out of the first square root as 3
in front and take 2² out of the second square root
as 2 in front, like this:
-6·3√7 - 9·2√7 + 2√14
-18√7 - 18√7 + 2√14
The first two terms combine as -36√7
-36√7 + 2√14
That's the simplest radical form.
Edwin
