5
Since there is a minus sign in front of the 4, you would first add four to itself and 21 to get 25 and then have 5n=25 (in terms of canceling out four). Next, divide 5n by itself (5) and 25 to get 5. So thus, n=5
(More improved answer by -iRoqNikes)
t(n) = (5n4 - 10n3 + 55n2 - 50n + 24)/24 where n = 1, 2, 3, ...
21 t(n) = (-5n4 + 66n3 - 271n2 + 450n - 216)/24, where n = 1, 2, 3, ...
21 equals dots on a dice
28*21 equals 84
21
5q-29 equals 21 5q equals 50 q = 5
21
21 feet equals 6.4008 metres.
3 and 7 multiplies to 21 and equals to 10
9 times 7/3 = 21
How about: 1*21 = 21 or 3*7 = 21
x = ab x = 21*37 x = 777