Question

Resolva a equação de 2°grau
F(x)=-1x²+2x+8=
Pfvor e pra amanhã

Answer 1

Resposta:

Para resolver a equação: f(x)=0

x²+2x+8= 0

-1$Aplicando~a~f\'{o}rmula~de~Bhaskara~para~-1x^{2}+2x+8=0~~\\e~comparando~com~(a)x^{2}+(b)x+(c)=0,~temos~a=-1{;}~b=2~e~c=8\\\\\Delta=(b)^{2}-4(a)(c)=(2)^{2}-4(-1)(8)=4-(-32)=36\\\\x^{'}=\frac{-(b)-\sqrt{\Delta}}{2(a)}=\frac{-(2)-\sqrt{36}}{2(-1)}=\frac{-2-6}{-2}=\frac{-8}{-2}=4\\\\x^{''}=\frac{-(b)+\sqrt{\Delta}}{2(a)}=\frac{-(2)+\sqrt{36}}{2(-1)}=\frac{-2+6}{-2}=\frac{4}{-2}=-2\\\\S=\{4,~-2\}$