Jawabanmu

2014-04-11T08:26:00+07:00
H=3
s=30
f=20

1/f=1/s+1/s'
-1/20=1/30+1/s'
-1/20-1/30=1/s'
-3/60-2/60=1/s'
-5/60=1/s'
-1/12=1/s'
-12=s'
1 5 1
2014-04-11T13:07:08+07:00
S = 30 cm
f = 20
jawab : 1/f=1/s+1/so 
1/so = 1/f-1/s
 1/so=1/20-1/30=3/60-2/60=1/60=60cm

ket : so+jarak bayangan 
jadi jarak bayangan adalah, 60 cm