A.) 3.2 pounds package has a shipping cost of $4.13. We can't use the cost assigned to 3 lbs because the package is over 3 lbs but it is not over 4 lbs so we use the cost of 4lbs.
b) It is better to use a line graph where x values represent the weight in pounds and the y values represent the cost.
c) f(x) = 2.69 + 0.48(x-1)
d) domain is the x values; range is the y values