Jawabanmu

2014-05-30T18:47:03+07:00
1/f = 1/s + 1/s'
1/7,5 = 1/15 + 1/s'
2/15 - 1/15 = 1/s'
1/15 = s'

   = s'/s
   =15 / 15
   = 1
perbesaran = 1

H = 3.1
   = 3 <<<<<