Here is a graph. When you use a graphing calculator, it isn't always necessary to solve for y.
Note different colors are used for the different problems. Problem 2 has a dashed line, as described by "Remember, ...".
Answer:
9
Step-by-step explanation:
Divide the change by the initial number to get a fraction and multiply by 100% to get a percent. The percent you get will describe the change in area in the mathematical language of numbers.