3let a be the absolute value relation on the set of real numbers, defined as: x a y # lx-lyl determine whether a is reflexive, symmetric, or transitive. if the answer is "yes," give a justification (full proof is not needed); if the answer is "no" you must give a counterexample. 4. let a-rx r, and let a relation s be defined as: (x1, y) s (x2, y2) x1-y2 determine whether s is reflexive, symmetric, or transitive. if the answer is "yes," give a justification (full proof is not needed); if the answer is "no" you must give a counterexample.