Jawabanmu

2014-04-09T18:15:16+07:00
22 = a+(7-1)b
22=a+6b

34=a+(11-1)b
34=a+10b

22=a+6b
34=a+10b
----------------  -
-12=a-4
-12+4=a
-8 = a

22=-8+6b
22+8 = 6b
30 = 6b
b=5

Un = -8(17)5
un = -8+ 85
Un = 77

sn = n/2 (a+un)
sn = 18/2 (-8+77)
sn = 9.69
sn = 621
kok a-a = a ? 6b-10b = -4 ?
a -a = habis kan
iya dong 6b-10b = -4
oh ya maaf typo
2014-04-09T18:33:16+07:00