Page 38 - E-MODUL FUNGSI KOMPOSISI DAN FUNGSI INVERS

2. f( ) = 2 - 7 dan ( )( ) = 6 + 4
( )( ) = g (f(x)) = 6 + 4

g (f(x)) = 6 + 4 5

g (2 - 7 ) = 6 + 4
g (x) = 6 (2x – 7) + 4

g (x) = 12x – 42 + 4

g (x) = 12x – 38
a. misalkan g(x) = y, maka

y = 12x – 38
y + 38 = 12 x 10

+38 +38
= x atau x =
12 12
– 1
g (x) = +38
12
– 1
b. g (10) = 10+38
12

48
– 1
g (10) =
12 5
– 1
g (10) = 4
3. f(x) = 5x + 6, g(x) = x - 2 dan h(x) = 3
(f o g o h) (x) = f (g (h (x)))
= f (g (3x)

= f (3x - 2)

= 5(3x - 2) + 6
= 15x – 10 + 6

= 15x – 4

Misalkan (f o g o h) (x) = y , maka
y = 15x – 4 20

y + 4 = 15x
+4 +4
= x atau x =
15 15
-1
(f o g o h) (x) = +4
15
-1
Berapa nilai x jika (f o g o h) (x) = 5 ?

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