So the answer choices are 1. a-b=even 2. a and b are not odd 3. a and b are odd 4. a-b=even 5. a-b=not even
even=not odd not even=odd so choice 5 is really a-b=odd basically choice 4 and 1 are the same so we cross one out so the problem said that a and b are odd so therefor choice2 is wrong and choice 3 is correct
then both are odd odd-odd=even because an even number is represented as 2n where n is an integer an odd number can be represented as 2n+1 so assume you have 2 odd numbers 2 away from each other so odd and (odd+2) odd+2-odd=2n+1+2-(2n+1)=2n+1+2-2n-1=2n-2n+1-1+2=2 you are left with odd using integers 7 and 11 11-7=4 even
so odd-odd=even, it depends on weather you consider 0 odd or even
so the asnwers are: a and b are odd a-b is not an even integer
