Respostas

2013-06-11T23:07:12-03:00

Bhaskara nela! 

 

Fórmula X = \frac {-b \ \frac{+}{-} \sqrt{b^{2} - 4.a.c}}{2a}  

 

onde:

a = -1\\ b = 8\\ c = -15\\ \\ Delta = 8^{2} - 4.(-1).(-15)\\ Delta = 64 - 60\\ Delta = 4\\ \\ x = \frac{-(8) +/-\sqrt{4}}{2.(-1)}\\ x = \frac{-8 +/- 2}{-2}\\ x_{+} = \frac{- 8 +2}{-2}\\ x_{+} = \frac{-6}{-2} = 3\\ x_{-} = \frac{- 8 -2}{-2}\\ x_{-} = \frac{-10}{-2} = 5\\