Respostas

2014-08-26T23:38:38-03:00
X²-6x+9 = 0
a= 1
b= -6
c= 9
Δ = b² - 4 ac
Δ = (-6)² - 4*1*9
Δ = 36 - 36
Δ = 0 
2014-08-27T00:42:15-03:00
 x^{2} -6x+9 =0 => x= \frac{6+- \sqrt{ (-6)^{2}-4*1*9 } }{2}=> x_{1}= \frac{6}{2}=3   as duas raízes são iguais, pois delta=0 :.