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nilai g diganti 10 sehingga
g(x) = x -1
= 10-1
= f (9)
f (x) = x² + 2x
9² + 2(9)
81 + 18
99
Baca Juga: Soal PAT Matematika Kelas 4 Semester 2 Kurikulum 2013 Beserta Pembahasan Kunci Jawaban 2022
3. f(x) = 3x + 1
g (x) = 2x – 4
(fog)ˉ¹ (x) =…
Jawaban :
Kita cari fog (x) = f (g(x)) terlebih dahulu
= f (2x – 4)
= 3 (2x – 4) + 1
= 6x – 12 + 1
= 6x – 11
Fungsi masih dalam keadaan y sehingga :
y + 11 = 6x
y + 11/6 = x
(fog)ˉ¹ (x) = x + 11/6
4. Jika f(x) = x² + 8x + 10 maka fˉ¹ (x)
y = x² + 8x + 10
jawaban :
y = x² + 8x + 10
y – 10 = x² + 8x + 16 (memakai kuadrat sempurna)
= (x + 4)²
y – 10 + 16 = (x + 4)
y + 6 = (x + 4)
√y + 6 = x + 4
√y + 6 – 4 = x
fˉ¹ (x) = -4 + √x + 6
5. Jika f (x) = 3x – 1/x – 5
Maka fˉ¹ (4) =…
