Respostas

2013-08-15T15:51:19-03:00
X² - x - 12 = 0
A= 1  B= -1  C= -12
delta= (-1)² - 4.1.(-12)
delta= 1 - (-48)
delta= 1 + 48 = 49

 \frac{-(-1) + ou -  \sqrt{49} }{2}

 \frac{1 + 7}{2} =  \frac{8}{2}   = 4 = x'
 \frac{1-7}{2} =  \frac{-6}{2}  = -3 = x"