Respostas

2013-08-07T13:14:37-03:00
Temos que:

F(x) = ax + b

F(-1) = a*(-1) + b
**************
7 = -a + b
b= 7 + a
**************

F(2) = 2a + b
1 = 2a + b

1 = 2a + 7 + a

-6 = 3a

**********
a= - 2
**********

b = 7 + a
b= 7 + (-2)
*******
b= 5
********

Portanto a função fica:

***************
f(x) = -2x + 5
***************
2 4 2