Can someone me with this. i have no idea what it means. also, explain what set builder notation and roster form are.

answer:

roster form is a representation of a set that lists all of the elements in the set, separated by commas, within braces.

step-by-step explanation:

sorry the answer i believe would be b because 1 x 12=12,   2 x 6=12,   3 x 4=12,

4 x 3=12, and   6 x 2=12

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons