What is the answer to this question

Solve the word problem. the table shows the low outside temperatures for monday, tuesday, and wednesday. by how many degrees did the low temperature increase from monday to tuesday? this function table shows the outside temperature for a given a. 21.1⁰ b. 8.6⁰ c. 4.9⁰ d. 3.9⁰(the picture is the graph the the question is talking about.)

With this one. will mark brainliest

1- 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. 2- 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. 3- 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 part b?