Question

How to solve 8 = 2^x + 4?

Answer 1

You are looking for what +4 = 8 so you take the 2^x and find what would make that 4. 2 squared is 4 (2x2) which makes 8=4+4

4+4=8 8=8

Answer 2

8 = 2^x + 4
2^x = 8 - 4
2^x = 4
as you know 4 = 2^2 so now you have:
2^x = 2^2
   x = 2