Thanks for all the help

What is the missing constant term in the perfect square that starts with x^2 -20x

1jessica's home town is a mid-sized city experiencing a decline in population. the following graph models the estimated population if the decline continues at the same rate. select the most appropriate unit for the measure of time that the graph represents. a. years b. hours c. days d. weeks

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.