Jawabanmu

2014-01-25T18:31:27+07:00
F (g (x)) = f (2x + a + 1)
           = 2 - (2x +a+1)
           = 2 - 2x - a - 1
           = - 2x - a  + 1
g (f(x)) = g (2-x)
          = 2 (2-x) + a + 1
          = 4 - 2x + a + 1
           =  -2x + a + 5
f (g (x)) = g (f(x))
-2x - a + 1 = -2x + a + 5
- 2 a = 4
Jadi, a = 4 / -2 = - 2