Answer
$(1-10y)(1+10y)$
Work Step by Step
This is a difference between two squares, and hence
$$1-100y^2=(1-10y)(1+10y).$$
One can check as follows
$$(1-10y)(1+10y)=1-10y+10y+100y^2=1-100y^2
.$$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.