Math Problem Solver

Give proofs using contrapositive of the following statements.

1. For integers xy, if x+y is even, then x and y are both odd or both even.

2. For an integer n, if n^2 < 20, then n < 5.

3. For an integer x, if x^2 6x+5 is even, then x is odd.

4. For an integer m, if m^2 is not divisible by 4, then m is odd.

5. For real numbers x and y, if xy is an irrational number then x is irrational

or y is irrational.