Resposta :
[tex]x^{2}+4x-5=0[/tex]
/\= [tex]4^{2}-4.a.c[/tex]
/\= [tex]16-4.1.-5[/tex]
/\= [tex]16 + 20[/tex]
/\= [tex]36[/tex]
[tex]x = \frac{-b \limitis^+_-\sqrt{/|}}{2.a} \\ x = \frac{-4 \limitis^+_-\sqrt{36}}{2.1} \\ x = \frac{-4 \limitis^+_-6}{2} \\ \\ x'= \frac{2}{2} =1\\ \\ x''= \frac{-10}{2} =-5 [/tex]