I've created methods for each of the math equations. I've assigned numbers to x and n and i've called the method. What's the problem?

You got errors at compile or in running?

Maybe "Math" is a reserved name on your compiler

are you confusing "not running" with "not giving output"? you dont write to the console, so if it runs, you probably wouldn't know.

You're right my bad. I added system.out.println and got the answers.