Some of the arguments in 718 are valid by universal modus ponens or universal modus tollens; others are invalid and exhibit the converse or the inverse error. State which are valid and which are invalid. Justify your answers.

Question:

If an 8-bit twos complement represents a positive integer, then the 8-bit twos complement starts with a 0.

The 8-bit twos complement for this integer does not start with a 0.

This integer is not positive.