Jawabanmu

2014-04-09T19:39:37+07:00
F(x) = ax+b
f(1) = a.1+b = a+b
f(3) = 3a+b
dieliminasi maka 
f(1)-f(3) = -2a 
f(3) = 2a+3

2014-04-09T19:42:27+07:00
F(3)=5-2x²
    = 5 - 2 . 3²
    = 5 - 2 . 9
    = 5 - 18
   = -13