Now let's get this straight. Your problem is:show that if A-B-C and B-C-D,then A-B-D and A-C-D
That doesn't make any sense, as I told you before. Suppose A=7, B=3, C=2, D=1. A-B-C = 7-3-2 = 2 B-C-D = 3-2-1 = 0 A-B-D = 7-3-1 = 3 A-C-D = 7-2-1 = 4 Let's substitute those values in what you wrote, which was:show that if A-B-C and B-C-D,then A-B-D and A-C-D
We get:show that if 2 and 0,then 3 and 4
Do you think that makes any sense? If so, you are the only person on the planet who thinks it does. Edwin