Jawabanmu

2014-04-23T22:26:28+07:00
Si= So x F : (So-f)
= 4 x 5 : ( 4-5)
=20 : (-1) 
=-20
11 + 1
5    4     Si
1 = 1-1 = 4-5 = -1
si   5-4    20      20
=20 = -20
  -1