Respostas

2014-01-27T14:40:44-02:00
Olá.

x²-3x-28=0
a=1 b= -3 c=-28
Δ= (-3)² -4·1·(-28)
Δ= 9+112
Δ= 121

 x= 1 +/-11
         2
x'= 6
x''= -5

S:[-5,6]