Answer
a. If P is not a rectangle, then P is not a square.
b. If tomorrow is not January, then today is not New Year's Eve.
c. If r is not rational, then the decimal expansion of r is not terminating.
d. If n is not odd and n is not 2, then n is not prime.
e. If x is not positive and x is not 0, then x is not nonnegative.
f. If either Jim is not her uncle or Sue is not her aunt, then Tom is not Ann's father.
g. If either n is not divisible by 2 or n is not divisible by 3, then n is not divisible by 6.
Work Step by Step
Recall that the contrapositive of p $\rightarrow$ q is ~q $\rightarrow$ ~p.
For sentences involving AND or OR, recall De Morgan's Laws:
The negation of AND: ~(p ∧ q) ≡ ~p∨ ~q
The negation of OR: ~(p ∨ q) ≡ ~p∧ ~q