Please help ! Solve for r. 5!/(5-r)! =20?
回答 (3)
2016-01-06 1:53 am
5! / (5 - r)! = 20
5! / 20 = (5 - r)!
120 / 20 = (5 - r)!
6 = (5 - r)!
n! = 6
n = 3
5 - r = n
5 - r = 3
r = 5 - 3
r = 2
5! / 20 = (5 - r)!
120 / 20 = (5 - r)!
6 = (5 - r)!
n! = 6
n = 3
5 - r = n
5 - r = 3
r = 5 - 3
r = 2
2016-01-06 3:39 am
5!/(5 - r)! = 20
5! = 20(5 - r)!
120 = 20(5 - r)!
6 = (5 - r)!
r = 2
5! = 20(5 - r)!
120 = 20(5 - r)!
6 = (5 - r)!
r = 2
2016-01-06 1:43 am
(5*4*3*2*1) / (5 - r)! = 5*4
So (5 - r)! must be 3 * 2 * 1 or 3!. That tells you what r is.
So (5 - r)! must be 3 * 2 * 1 or 3!. That tells you what r is.
收錄日期: 2021-04-21 16:13:21
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