I think factored form for your problem should be 2 (2x^2 - 9y^2). I hope this is what you were asking for sorry if I'm incorrect. All I did was find the biggest most common factor that they shared which is 2 because 1 is smaller than 2 and 3 doesn't go into 4 and 4 doesn't go into 18. Finally every number passed 4 wouldn't be able to go into 4. Welcome
