I need help figuring out the answer

The graph shows the prices of different numbers of bushels of corn at a store in the current year. the table shows the prices of different numbers of bushels of corn at the same store in the previous year. previous year number of bushels price of corn (dollars) 2 10 4 20 6 30 8 40 part a: describe in words how you can find the rate of change of a bushel of corn in the current year, and find the value. part b: how many dollars more is the price of a bushel of corn in the current year than the price of a bushel of corn in the previous year? show your work.

Need on this geometry question. explain how you did it.

The product of (7x-2) and (20-3x)/4. when x=4