Use proof by contrapositive For integers x and y if xy is od

Use proof by contrapositive:

For integers x and y, if xy is odd, then x is odd and y is odd

Solution

For integers x and y, if xy is odd, then x is odd and y is odd

by Contrapositive

if x is even and y is even then xy is always even

OR

if x is odd and y is even then xy is always even

OR

if x is even and y is odd then always even

so, we can infer from above 3 statements that

if x and y both are odd then only xy will be odd