+1911 What is the greatest common factor of $(a^2 - 9)$ and $(3a^2 - 3a)$?
+120 It should be 3a notice that you can open (a^2-9) into a (a + 3 ) x (a - 3 ) and (3a^2-3a) into 3a ( a - 1 )
It should be much easier to recognize the gcf in both equations once you open them up
