When 3 sides of a triangle are given, only 1 triangle can be formed...remember SSS => congruence.
If only 2 of the lengths are given and equal and the third can vary, then a triangle can be formed as long as the third side is less than twice the other given side.
As I think about this question, I wonder if you copied the problem correctly. The answer I gave you is correct, but I'm not sure it is what you meant to ask.
