(20pts) Prove that the product of any two odd numbers is always odd. Make sure to explain your proof

See below (I hope this helps!)

Step-by-step explanation:

Because odd numbers are always 1 greater than even numbers, we can call the two odd numbers x + 1 and y + 1 where x and y are even integers. Multiplying the two gives us:

(x + 1) * (y + 1)

= x * y + x * 1 + 1 * y + 1 * 1

= xy + x + y + 1

We know that x * y will be even because x and y are also even and the sum of two even numbers will be even, and we also know that x and y are even and that 1 is odd. Since the sum of even and odd numbers is always odd, the product of any two numbers is always odd.

*NOTE: I put a limitation on x and y in my proof (the limitation was that x and y must be EVEN integers) but you don't have to do that, you could make the odd integers 2x + 1 and 2y + 1 where x and y could be any integer from the set Z like mirai123 did. I simply gave this proof because it was the first thing that came to mind. While mirai123's proof and mine are different, they are still both correct.

Prove that the product of any two odd numbers is always odd.

Examples:

Defining an odd number as:

Yes, it is, because

An even number plus one is an odd number.

go on the tube you might find some information there