Show that the following set of sentences is inconsistent:
a.) Dogs that don't ever bark always bite.
b.) There is a dog with soft fur and no teeth.
c.) Dogs that bite are never friendly and they always have teeth.
d.) Dogs that have soft fur are friendly and they never bark.

Identify the predicate, function symbols (if there are any), variables(if there are any), and constants(if there are any)
1) x+y=z
2) 0<_(less than or equal to symbol)