Question

Factor completely: −9a^2 + 18a − 27

Answer 1

Factor out -9 first

Answer 2

http://www.wolframalpha.com/input/?i=%E2%88%929a%5E2+%2B+18a+%E2%88%92+27

Answer 3

\[−9a^2 + 18a − 27=-9(a^2-2a+3)\]Note that \[b^2-4ac<0\]

Answer 4

So there are no real roots, i.e., not factorable (further) with real coefficients.