Jika f(2x+4)=x dan g(3-x)=x, maka nilai f(g(1))-g(f(2)) sama dengan

1. 3 - x = 1
x = 2
g(3 - 2) = 2
g(1) = 2

2. 2x + 4 = 2
2x = -2
x = -1
f(2(-1) + 4) = -1
f(2) = -1

f(2) - g(-1)
2 - (-1)
= 3

f(2x + 4) = x
Misal 2x + 4 = a => 2x = a - 4 => x = (a - 4)/2
f(a) = (a - 4)/2
f(2) = (2 - 4)/2 = (-2)/2 = -1

g(3 - x) = x
Misal a = 3 - x => x = 3 - a
g(a) = 3 - a
g(1) = 3 - 1 = 2
g(-1) = 3 - (-1) = 4

f(g(1)) - g(f(2)) = f(2) - g(-1) = -1 - 4 = -5