Can you take the 2's complement of an already negative number?

Question

So for example, if we were to try and take the 2's complement of -8. Would this be un-representable or would doing the 2's complement result in a positive 8?

Answer 1

$-8$ when converted to binary gives $11111000$

Flipping the digits give $00000111$

Add $1$ we get $00001000$ which is equal to $8$