Di berikan fungsi f(x) yang di definisikan f(x)= x-1, g(f(x)) = 2x²-4x-5 tentukan g(x) dan g(2x + 1)

g(f(x)) = 2x²-4x-5

f(x) =x-1

maka g(f(x)) = g(x-1) = 2x²-4x-5

permisalan=

x-1 =a

x = a + 1

kembali ke g(x-1) = g(a) = 2(a+1)² -4a – 5

g(a) = 2(a²+2a+1) -4a -5

g(a) = 2a² + 4a + 2 -4a -5

g(a) = 2a² -3

g(x) = 2x²-3

dan g(2x +1) = 2(2x-3)² -3

= 2(4x²-12x + 9) -3

= 8x²-24x +18 -3

= 8x² -24x +15