Jawabanmu

2014-06-02T14:35:35+07:00
1/s' = 1/f - 1/s
1/s' = 1/12 - 1/8
1/s' = 1/6 - 1/4 (disederhanakan)
1/s' = 4-6/24
s' = 24/-2
s' = -12
2014-06-02T14:36:56+07:00
-1/f=1/So + 1/s'
-1/12=1/8 + 1/s'
-1/12-1/8=1/s'
-2/24-3/24=1/s'
-5/24=1/s'
-24/5=s'
-4.8 cm=s'