1).F(x-4) = 4x+1 F(-1) = ........ 2).f(3x+1)= 6x+5 F(1/2) =.........

1) x-4= -1
x=3
f(-1)= 13

2) 3x+1=1/2
x= -1/6
f(1/2)= 4


maaf kalo salah

Mapel : Matematika

Kelas : 8

Bab : Relasi dan Fungsi
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1] f(x - 4) = 4x + 1

Misalkan

x - 4 = y

x = y + 4

Maka, nilai f(x)

f(x) = 4(x + 4) + 1
f(x) = 4x + 16 + 1
f(x) = 4x + 17

Jadi, nilai fungsi f(-1)

= 4(-1) + 17
= -4 + 17
= 16 ✔


2] f(3x + 1) = 6x + 5

Misalkan :

3x + 1 = y
3x = y - 1
x = (y - 1)/3

Maka, nilai f(x)
f(x) = 6(x - 1)/3 + 5
f(x) = 2x - 2 + 5
f(x) = 2x + 3

Sehingga, nilai fungsi f(1/2)

= 2(1/2) + 3

= 1 + 3

= 4 ✔