Respostas

2013-10-23T23:30:16-02:00
F(1) = a + b = 3
f(3) = 3a + b = 5
então,

 \left \{ {{a+b=3} \atop {3a+b=5}} \right.

 \left \{ {{a+b=3}.(-1) \atop {3a+b=5}} \right.

 \left \{ {{-a-b=-3} \atop {3a+b=5}} \right.

2a = 2

a= \frac{2}{2}  = 1

a + b = 3
1 + b = 3
b = 3 - 1 = 2

Sendo assim a = 1 e b = 2

RESPOSTA
f(x) = x + 2