Respostas

2013-11-08T13:52:12-02:00
3) ∆>0
  b^2-4ac>0\\4^2-4.2.5k>0\\16-40k>0\\-40k>-16\\k< \frac{16}{40}\\k< \frac{2}{5}

4) ∆=0
b^2-4.a.c=0\\(p+5)^2-4.1.36=0\\p^2+10p+25-144=0\\p^2+10p-119=0
∆=10^2-4.1.(-119)
∆=100+476
∆=576

p= \frac{-10+- \sqrt{576} }{2.1}\\p=  \frac{-10+-24}{2}\\p'= \frac{-10+24}{2}= \frac{14}{2} =7\\p''= \frac{-10-24}{2}= \frac{-34}{2}=-17

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