When evaluated, which expression has a result that is a rational number?

Classify the following triangle check all that apply

Adrawer contains 12 identical white socks, 18 identical black socks and 14 identical brown socks. what is the least number of socks you must choose, without looking, to be certain that you have chosen two socks of the same colour?

X+y=-4 x-y=2 use elimination with adding and subtraction