Tolong no 6 dan 7 ya kak, terimakasih.

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Nomor 6
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Diketahui :
f(x) = 2x² - 2 dan
g(x) = 1/2x + 2

maka (fog)(x) =
= f(g(x))
= 2(1/2x + 2)² - 2
= 2.(1/4 x² + 2x + 4) - 2
= 1/2 x² + 4x + 8 - 2
= 1/2 x² + 4x + 6

Jawaban : E



Nomor 7
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Diketahui :
f(x) = 2x - 1 dan (fog)(x) = (5x + 1) / (x - 1)

Tanya : 
g(x) = ___?

Jawab :


(fog)(x) = (5x + 1) / (x - 1)
(f(g(x))  = (5x + 1) / (x - 1)

2(g(x)) - 1 = (5x + 1) / (x - 1)
2(g(x)) = (5x + 1) / (x - 1) + 1
2(g(x)) = (5x + 1) / (x - 1) + (x - 1) / (x - 1)

2(g(x)) = (5x + 1) + (x - 1) / (x - 1) 

2(g(x)) = 5x + 1 + x - 1 / (x - 1) 
 
2(g(x)) = 6x / (x - 1) 
 
g(x) = 3x / (x - 1)

Jawaban : A

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FZA