Jawabanmu

2014-04-06T15:34:34+07:00
U7 ⇒  a+6b  = 35
U11⇒ a+10b = 51( -)
              -4b = -16
              b   =  4

a+6b = 35
a+6(4)=35
a+24   =35
a         = 35- 24
a         = 11

U18 ⇒ a+17b= 11 + 17 (4)
                    = 11 + 68
                    = 79
2014-04-06T15:37:21+07:00
U7 = 35 u11 = 51 ditanya u18? a+6b = 35 a+10b = 51 dieliminasikan b = 4 a+6b = 35 a+6(4) = 35 a = 35 - 24 a = 11 dicari u18? u18 = a+(n-1)b u18 = 11+(17)4 u18 = 11+68 u18 = 79