help, ini gimana ya caranya? susah banget

f(x) = f(3)x^2 + f(2)x - 4

f(-1) = f(3) (-1)^2 + f(2) (-1) - 4
f(-1) = f(3) - f(2) - 4

Cari nilai f(3) dan f(2)
f(3) = f(3) (3)^2 + f(2)3 - 4
f(3) = 9f(3) + 3f(2) - 4
8f(3) = 4 - 3f(2)

f(2) = f(3) (2)^2 + f(2)2 - 4
f(2) = 4f(3) +2f(2) - 4 (×2)
2f(2) = 8f(3) + 4f(2) - 8
2f(2) = 4 - 3f(2) + 4f(2) - 8
f(2) = - 4

Masukkan nilai f(2)
8f(3) = 4 - 3f(2)
8f(3) = 4 - 3(-4)
8f(3) = 4 + 12
8f(3) = 16
f(3) = 2

Masukkan nilai keduanya
f(-1) = f(3) - f(2) - 4
f(-1) = 2 + 4 - 4
f(-1) = 2

Jawabannya C (2)

smg membantu :)