Discrete Math State precisely but concisely what it means fo

Discrete Math:

State precisely (but concisely) what it means for a number r to be rational.

a) A real number r is rational if, and only if, r = a/b for some integers a and b with b 0.

b) There is a real number r such that for all real numbers z, rz = 1

c) A real number r is rational if, and only if, r = b/a for some integers a and b with b 0

d) A real number r is rational if, and only if, r = ab for some integers a and b with b 0

Solution

State precisely (but concisely) what it means for a number r to be rational.

hence option a is correct

A real number r is rational if, and only if, r = a/b for some integers a and b with b 0.