How do you split the middle term in factoring?

Question

For example

x(squared) + 4xy + 4y(squared)

Answer 1

the answer is = (x+2y)(x+2y)

or just (x+2y)squared.

its not like you split the middle number... but heres how you figure it outtt...

since its just x, its the same as 1x, rightt?

and then you have 4y on the other side.

so you can break down that 4y into 2 and 2

so thats how you get the answer.

wow. thats really confusing to put into words...