Which of the following demonstrates how the first 21 (on the left side of the triangle) is calculated using the combination pattern?
1
(
1
1
1
2
1
1
3
3
1
1
4
6
4
1
1 5 10 10 5 1
16 15 20 15 6 1
1 7 21 35 35 21 7 1
OA
71
- 21
(7-2)121
o
B.
2162
211
- 21
(21-2)121
-~-
---
-C)
-(1)-
Ос.
216
211
(21-7)171
-21
D
71
- 21
(7-7)17!

This question awards 100 ! i really don’t want to fail i will also mark you !

The krasnapolski is a top-of-the-line hotel in amsterdam, the netherlands. among their many services, they rent bicycles to guests. the bicycle checkout is open 24 hours per day 7 days per week and has 50 bicycles on hand. on average, 10 guests request a bicycle each day, arriving completely randomly at all times of the day during the spring and summer seasons. guests keep bicycles for four days on average, with a standard deviation of two days. how long does a guest on average have to wait for a bike? a. approximately 24 hours b. approximately 0.033 hours c. approximately 4 days d. approximately 47 minutes

Solve the equation by completing the square. x^2+2x=17