A These are multiples of 3 so 3x where x is a natural number from 0 to 4. In set builder notation we get {3x | x c Z, 0<= x <= 4} By c I mean the symbol for “is an element of” which looks like a drawn out rounded upper case E. By <= I mean less than or equal to
B These are integers from -3 to 3. That is {x| x c Z, -4 < x < 4
C Here we have letter from the English alphabet from m to p. {x| x c letter of the English alphabet from m to p}