If two of the four expressions x+y,x+5y,x-y,5x-y are chosen at random, What is the probability that their product will be of the form x^2- (by)^2, Where b is an integer
1)1/2
2)1/3
3)1/4
4)1/5
6)1/6
1)1/2
2)1/3
3)1/4
4)1/5
6)1/6
