Please answer all of the questions. I will give brainiest to best )

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

Factor the expression using the gcf. the expression 21m−49n factored using the gcf

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?