how do you do this problem?

The x is called power, in order to find it you count how many times you need to repeat the 2 in order to get 8.
x = 3
Because [tex]2^{3}[/tex] = 8, this means you repeated the number 2 three times to get 8.
In other words, you multiply 2 by itself three time like this: 2 × 2 × 2 = 8