32. Jika 𝑔(𝑥) = 4𝑥 + 3 dan (𝑓 𝑜 𝑔)(𝑥) = 8𝑥 − 6, maka rumus 𝑓(𝑥) = ...
A. 2𝑥 − 14
B. 2𝑥 − 12
C. 2𝑥 − 10
D. 2𝑥 − 8
E. 2𝑥 − 6
Jawaban :
𝑔(𝑥) = 4𝑥 + 3
(𝑓 𝑜 𝑔)(𝑥) = 8𝑥 − 6
f (g (x)) = 8x - 6
f (4x + 3) = 8x - 6
misalkan :
a = 4x + 3
4x = a - 3
x = 1/4 (a - 3)
f (4x + 3) = 8x - 6
f (a) = 8 (1/4 (a - 3)) - 6
f (a) = 2 (a - 3) - 6
f (a) = 2a - 12
sehingga,
f (x) = 2x - 12
Jawaban : B
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