Ineed asap, this is my last question for my

at a book fair, scott bought a 4$ tote bag and some books for 2$ each. the total amount scott spent is represented by the equation below.

y= 2x + 4

what does the variable x represent in this equation?
a. the cost for one book
b. the total amount spent
c. the number of books bought
d. the cost of all the books bought

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z