Question:
Sum, product of rational and irrational number
1. Prove or disprove each of the following:
a. The sum of a rational number and an irrational number is an irrational number.
b. The product of two rational numbers is a rational number.
c. The product of two irrational numbers is an irrational number.
d. The product of a rational number and an irrational number is an irrational number.