Decide, with justification, on the truth of the followingpropositions, both when the Universe of discourse is the set of allpositive integers, and when the Universe of discourse is the set ofall real numbers.
1. ?x?y, x < x·y
2. ?y?x, x < x·y
3. ?x?y, x = x·y
4. ?y?x, x = x·y
5. ?x?y,?z, y2 ? z2 = 4x
6. ?x?y?z, z < x2 + y2
7. ?x?y?z, x > yz.
