1. Diketahui f(x)= x²-2x-8 dan g(x) = x²+3x+2. Tentukan f(-1) dan (gof)(-1)

1)
f (x) = x² – 2x – 8
g (x) = x² + 3x + 2

f (-1) = (-1)² – 2.(-1) – 8
       = 1 + 2 – 8
       = -5

gof (-1) = g (f (-1))
           = g (-5)
           = (-5)² + 3.(-5) + 2
           = 25 – 15 + 2
           = 12

2)
f(x)=x² – 4x – 5
g(x) = 15 / (x + 3)

fog (-2) = f (g(-2))
             = f (15 / (-2 + 3))
             = f (15)
             = 15² – 4.15 – 5
             = 225 – 60 – 5
             = 160

1) f(x) = x² – 2x – 8
f(-1) = (-1)² – 2(-1) – 8 = 1 + 2 – 8 = -5

g(x) = x² + 3x + 2
(g o f)(-1) = g(f(-1)) = g(-5) = (-5)² + 3(-5) + 2 = 25 – 15 + 2 = 12

2) g(x) = 15/(x + 3)
=> g(-2) = 15/(-2 + 3) = 15/1 = 15

f(x) = x² – 4x – 5
(f o g)(x) untuk x = -2
(f o g)(-2) = f(g(-2)) = f(15) = 15² – 4(15) – 5 = 225 – 60 – 5 = 160