101010 divisible by 5 implies one of (a-b) and (a+b) is divisible by 5, notOriginally Posted byDenMac21

that one of them is 5. Also if one were 5 the other need not be divisible

by 5.

Because it must be then it must be .

So, we have to solve system of equations in order to see whether are integers.

Since is not integer then b is not integer.

Is this proof valid?