Respostas

2014-05-29T17:38:44-03:00
f(x)=(3+x).(2-x)  \\ \\a) f(0)=(3+0).(2-0) \\ f(0)=3.2 \\ f(0)=6 \\  \\ f(5)=(3+5).(2-5) \\ f(5)=8.(-3) \\ f(5)=-24

b)(3+x).(2-x)=-14 \\ 6-3x+2x-x^2=-14 \\ -x^2-x=-14-6 \\ -x^2-x=-20 \\ -x^2-x+20=0

Δ = (-1)^2-4.(-1).20
Δ = 1+80
Δ = 81

X =  \frac{-(-1)+- \sqrt{81} }{2.(-1)} =>X =  \frac{1+-9}{-2}

x' =  \frac{1+9}{-2}=> \frac{10}{-2} =-5                          x" =  \frac{1-9}{-2} => \frac{-8}{-2}=4

S = {- 5, 4}