Question

Fungsi g didefinisikan dengan rumus g(x) = qx + r Nilai g(3)= -12 dan g(-4) = 23. Nilai g(5) adalah...
A.11
B.-18
C.-20
D.-22

Answer 1

G(x) = qx + r

g(3) = 3q + r............(i)
g(-4) = -4q + r..........(ii)

-4q + r = 23
 3q + r = -12    -
-7q      = 35
   q      = -5

-4q + r = 23
-4(-5) + r = 23
20 + r = 23
r = 23 - 20
r = 3

g(5) = 5q + r
        = 5(-5) + 3
        = -25 + 3
        = -22

Answer 2

Cari nilai q :
( 23 + 12 ) : ( -4 - 3 ) = 35 : -7 = -5

Cari nilai r :
g(3) = -12
 -12 = -5(3) + r
 -12 = -15 + r
     r = 3

Maka, g(5) :
g(5) = -5(5) + 3
       = -25 + 3
       = -22 ==>> (D.)