this is the problem i think i got the answer wrong or one of the steps?
here it is
this is what i did
y^2-4xy+4x^2
-4xy=2 times x times -2y
(x)^2 + 2 times x times -2y -(2y)^2
the answer i got was
(y+2y)(y-2y) :lol: :mrgreen:

if this was a difference of two squares, there wouldn't be a middle term. if you have two squares and a middle term, chances are that is a trinomial square.