What is the factored form of the expression? 4x^2-18y^2

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