$15.$ For the two examples in Problem $14($the examples, not the problems in a$),$ b$),$ c$)),$ determine:

a$.$ if unsigned overflow occurred. Hint: just like addition, unsigned overflow is identified by the result carry, but opposite of addition, in subtraction carry $=0$ indicates overflow

b$.$ if signed overflow occurred. Hint: the rules for signed overflow are different for subtraction than addition, but they are also intuitive