How would I solve these questions

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.

Combine like terms to make a simpler expression 3z+z

The interior angles formed by the side of a hexagon have measures of them up to 720° what is the measure of angle a