Respostas

2013-12-17T01:54:17-02:00
F(x) = -4x + 20

a)f (-2) = -4 . (-2) + 20 = 8 + 20 = 28
b)f (1/2) = -4 . (1/2) + 20 = -4/2 + 20 = -2 + 20 = 18
c)f (0) = -4 . 0 + 20 = 20
d) f (x) = 0
-4x + 20 = 0
-4x = -20
-x = -20/4
-x = -5 (-1)
x=5