Question

Tentukan nilai a dan b jika f(x)=Ax+b,f(1)=3 dan f(-2)=-12

Answer 1

Verified answer

F(x)=Ax+b
f(1)=1A+b=3
f(-2)=-2A+b=-12
------------------------ (Eliminasi) (-)
3A=15
A=15/3  = 5
A+b = 3
5+b=3
b=3-5
b=-2

Answer 2

Verified answer

F(x) = ax + b
f(1) = a + b = 3............................1)
f(-2) = -2a + b = -12.....................2)

> Eliminasikan pers.1 dan 2

   a + b = 3
-2a + b = -12 -
       3a = 15
         a = 15/3
         a = 5

> Substitusikan a ke pers.1 atau 2

Misal ke pers.1 menjadi :
a + b = 3
5 + b = 3
      b = 3-5
      b = -2

∴ a = 5, b = -2