questions 13

29. To determine the appropriate landing speed of an airplane, the formula D=.1×2−3x+22 is

used, where x is the initial landing speed in feet per second and D is the distance needed in feet.

If the landing speed is too fast, the pilot may run out of runway; if the speed is too slow, the

plane may stall. What is the appropriate landing speed if the runway is 800 feet long? Show all

of your work or explain how you came up with your solution

30. The national catch of Atlantic Cod has been declining in the past few decades. We can model

this decline with the equation y=−.003×2+.120x+1.909 where x is the number of years since

1950 and y is the catch in millions of metric tons. In which year did the catch reach its

maximum? In which year will the catch reach 0? For what years was the catch increasing?

Decreasing? When was the catch greater than 2.5 million metric tons? Show all of your work or

explain how you came up with your solutions.