I need help with this factorization problem?

Question

How can I factorize this problem:

$1-8xy-x^2-16y^2$

I noticed that there are common terms, but how should I proceed ?

Answer 1

$$1-8xy-x^2-16y^2=1-(x^2+(4y)^2+2x\cdot 4y)=1^2-(x+4y)^2=(1+x+4y)(1-x-4y)$$

Answer 2

proof:

$1-(4y+x)^2=(1-4y-x)(1+4y+x)$