Diketahui f(x)= x kuadrat dan g(x)= 1-2x. Jika (f o g)(a) = 25, nilai a=....

f(x) = x^2 dan g(x) = 1-2x
fog (a) = 25
f { g(a) } = f (1-2a)
=> (1-2a)^2 = 25
=> 1 -4a + 4a^2 = 25
=> 4a^2 -4a -24 = 0
=> a^2 -a -6 = 0
=> (a -3)(a +2) = 0
a = 3 atau a = -2

Materi : Fungsi Komposisi

f(x) = x²
g(x) = 1 - 2x
diktahui (fog)(a) = 25
maka

(fog)(a) = 25
f(g(a)) = 25
f(1 - 2a) = 25
(1 - 2a)² = 25
1 - 2a - 2a + 4a² = 25
4a² - 4a - 24 = 0
a² - a - 6 = 0
(a + 2)(a - 3) = 0
a = -2   atau   a = 3

jadi a = {-2 , 3}