Question 504877
Guess and check is probably the best method here. We know that b cannot be 3, otherwise c would be 3 and we want all integers to be different. If b = 2, then c = 4, d = 3, and a = 6. Or, if b = 4, then c = 3, a = 8, etc. If your equation "a = c+2" is a given condition, then I would go with the first solution (a,b,c,d) = (6,2,4,3).