Diketahui fungsi
f(x) = 2 – a/2 x dan
g(x) = 2 – ( a – 3 )x.
Jika f(x) = g(x) maka
a. Nilai a
b. Bentuk fungsi f(x) dan g(x)
c. Bentuk fungsi f(x) + g(x)
d. Nilai f(-1) , f(2) , g(1) , g(4)
Jawab :
f(x) + g(x)
= ( 2 – 3x ) + ( 2 – 3x )
= 2 – 3x + 2 – 3x
= 2 + 2 – 3x – 3x
= 4 – 6x
f(x) = 2 – 3x
f(–1) = 2 – 3x = 2 – ( 3 . –1 ) = 2 + 3 = 5
f(2) = 2 – 3x = 2 – ( 3 . 2 ) = 2 – 6 = –4
g(x) = 2 – 3x
g(1) = 2 – 3x = 2 – ( 3 . 1 ) = 2 – 3 = –1
g(4) = 2 – 3x = 2 – ( 3 . 4 ) = 2 – 12 = –10
Jadi ,
a. Nilai a = 6.
b. Bentuk fungsi f(x) = 2 – 3x dan g(x) = 2 – 3x
c. Bentuk fungsi f(x) + g(x) = 4 – 6x
d.
Nilai f(–1) = 5 ,
f(2) = –4 ,
g(1) = –1 ,
g(4) = –10