dikeahui R(x) = ax+b. Jika R(-2) = -4 dan R(-6) = 12. tentukan : 1. carilah a dan b 2. hitunglah R(25) 3. tulislah rumus R (x)

Fungsi
SMP Kelas VIII

1] Cari a dan b
R(x) = ax + b

R(-2) = -4
-2a + b = -4

R(-6) = 12
-6a + b = 12

Eliminasi
-2a + b = -4
-6a + b = 12
----------------- -
4a = -16
a = -16 / 4
a = -4

-2a + b = -4
-2(-4) + b = -4
8 + b = -4
b = -4 - 8
b = -12

2] hitung R(25)
R(x) = ax + b
        = -4x - 12
R(25) = -4(25) - 12
          = -100 - 12
          = -112

3]Rumus R(x)
R(x) = ax + b

a = -4
b = -12

R(x) = -4x - 12

Materi : Fungsi



R(x) = ax + b
R(-2) = -2a + b = -4
R(-6) = -6a + b = 12
          ---------------------- (-)
              4a = -16
                a = -4
subtitusikan a = -4 ke 
-2a + b = -4
-2(-4) + b = -4
8 + b = -4
b = -12

R(x) = -4x - 12

2.
R(25) = -4(25) - 12
          = -100 - 12
         = -112