The answer is no. Because solution (a,b) means x=a, y=b.and we have a-b=5. And (b,a) would mean x=b and y=a but then x-y=b-a=-(a-b)=-5≠5. So the pair (b,a) is not a solution.
The probability of rolling less than 7 is equal to the probability of rolling 1 or 2 or 3 or 4 or 5 or 6. That is 1/6 + 1/6 + 1/6 + 1/6 + 1/6 + 1/6 = 6/6. So any number from the dice can come up when you roll it because a perfect dice has 6 sides.
