2.25

Prove each statement. Proof by using cases

(a) If x is an integer, then x² + 5x - 1 is odd.

(b) If x and y are real numbers, then max(x, y) + min(x, y) = x + y.

(c) If integers x and y have the same parity, then x + y is even.

The parity of a number tells whether the number is odd or even. If x and y have the same parity, they are either both even or both odd