Jawabanmu

2014-01-17T12:38:48+07:00
N = 50

4275 = (2x + 1 + 2x + 50)25
4275 = (4x + 51)25
4275 = 100x + 1275
100x = 3000
x = 30
2014-01-17T13:34:35+07:00
A= 2x+1
b= 1
n= 50
Sn = n/2(2a+(n-1)b)
4275= 50/2 (2(2x+1)+(49))
4275= 25(4x+51)
4275= 100x+1275
100x=1275-1275
100x=3000
x= 30