Respostas

2013-09-12T15:34:11-03:00
3 x²- 15x +12=0 (: 3)
 x²-5x+4=0
Δ=25-16x=5+-4/2
x1=9/2
x2=1/2
2013-09-12T15:45:31-03:00
A) a = 3 b = - 15 c = 12
b) a = 10 b = 72  c = - 64
c) a = 1 b = 6 c = 9
 d) a = 3 b = - 1 c = 3
e) a = 2 b = -2 c= -12
f) a = 3 b= - 10 c = 3  todas completas