Question

Suatu fungsi ditentukan dengan rumus f(x) = ax + b. Jika f(-2) = 17 dan f(5) = -32, f(12) = ....

Answer 1

-2a+b=17
5a+b=-32
-------------- -
-7a=49
a=-7
-2a+b=17
b=17-14
b=3
f(12)=-7*12+3=-81

Answer 2

 f(x) = ax + b
f(-2) = a(-2) + b = -2a + b = 17
f(5) = a(5) + b = 5a + b = -32
-2a+b= 17
5a+b = -32 -
-7a    = 49
a       =  49/-7
a       = -7

f(5) = -35+b= -32
      = b= -32+35
         b= 3
f(12) = (-7)12 + 3 = -84 + 3= -81