Help in finding a topic

While I was studying for Level 1, I remember a topic in which we were presented with a company debt and equity structure and we were told to recalculate the company’s valuation figure if we were to inject so so amount of debt or equity. My memory on this is vague but if someone can help me figure out the exact book and topic, I will appreciate it. Thanks!

I believe this would probably be found in the Corporate Finance section.