Determine weather the following graph represents a function

You paint a 1/2 of a wall in 1/4 hour. how long will it take you to paint one wall

Need on this one asap im almost done with this subject

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.