How do I make this a product?

I tried solving it, but I ended up getting the incorrect answer. Here’s what I did:

a-b+a^2-b^2
(a-b)+(a-b)(a+b)
2(a-b)(a+b)

What did I do wrong?

How do I make this a product I tried solving it but I ended up getting the incorrect answer Heres what I did aba2b2 ababab 2abab What did I do wrong class=