Jawabanmu

2014-06-20T21:44:54+07:00
F(x) = x-2x+4 = -x + 4
g(x+1) = 2x-3
misal x+1 = a
            x = a-1
g(a) = 2(a-1)-3 = 2a -2 -3 = 2a -5 
g(x) = 2x -5

(fog)(x) = -(2x-5) + 4 = -2x +9
2014-06-20T21:59:10+07:00
Pertama
g(x+1) dijadika g(x) dengan cara mengetau inversnya

x+1=x'
x=x'-1
maka
g(x+1)=2x-3
g((x'-1)+1)=2(x'-1)-3
g(x')=2x'-2-3
g(x')=2x'-5
g(x)=2x-5

fog(x)=f(g(x)
f(x)=x²-2x+4
f((g(x))=(gx)²-2(gx)+4.........g(x)=2x-5. maka
f(g(x)=(2x-5)²-2(2x-5)+4
(4x²-20x+25)-4x+10+4=
4x²-24x+39