Removing pages from search engine results

Question

Hey everyone, I\'m a bit new to SEO. I built a one page website that initially utilized several pages (but are now removed), and it looks as if Google has indexed those so that

Answer 1

Use a robots.txt file: Robots.txt

example robots.txt:

User-agent: *
Disallow: /url1.html
Disallow: /url2.html