Let x and y be non-zero, rational numbers, and let z be an irrational number. In the first column of the table below is an expression. In the second column, determine whether the value of each expression is rational or irrational.
Expression Rational/irrational
x - y Rational or irrational
3z Rational or irrational
-2x Rational or irrational
y + z Rational or irrational
Expression Rational/irrational
x - y Rational
3z Irrational
-2x Rational
y + z Irrational