Jika g(x) = 3x + 7 dan (gof) = 3×2 – 9x – 8 , maka f(x) =
Jawaban Terkonfirmasi
G(x) = 3x+7
(gof)(x) = 3x² – 9x – 8
f(x) = ax² + bx + c
(gof)(x) = g(f(x))
3x² – 9x – 8 = 3.(f(x)) + 7
3x² – 9x – 8 = 3.(ax² + bx + c) + 7
3x² – 9x – 8 = 3ax² + 3.bx + .3.c + 7
3x² = 3ax² -9x = 3b.x -8 = 3c + 7
3 = 3a -9 = 3b -15 = 3c
a = 1 -3 = b -5 = c
f(x) = ax² + bx + c
= x² -3x – 5