Can somebody me with these questions?

At which value in the domain does f(x) =0?

What is the equation of a line passing through the point (6,1) and parallel to the line whose equation 3x=2y+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?