4+8/2 x [6-3] if you dont under stand / = divide pls help

Find two rational expressions that have the difference of 2-n/n-4

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?

Your food costs are $5,500. your total food sales are $11,000. what percent of your food sales do the food costs represent?