Question

-x²+2x+8=0 naum consigo resolver me ajudem

Answer 1

$- x^{2} +2x+8=0\\ \\ a=-1 \ \ \ \ b=2 \ \ \ \ c=8\\ \\ \Delta=b^2-4.a.c\\ \\ \Delta=2^2-4.(-1).8=4+32=36\\ \\ x=\frac{-b \pm\sqrt {\Delta}}{2a}\\ \\ x=\frac{-2 \pm \sqrt{36}}{2.(-1)}=\frac{-2 \pm6}{-2}\\ \\ x_1=\frac{-2-6}{-2}=\frac{-8}{-2}=4\\ \\ x_2=\frac{-2+6}{-2}=\frac{4}{-2}=-2$

Answer 2

Olá

-x²+2x+8=0 
a=-1,b=2,c=8
Δ=b² -4. a .c
Δ=2² -4 . (-1) .8
Δ=4+32
Δ=36

  x=-b+-√Δ
_______________
       2.a

  x1= -2+√36/2.-1
x1= -2+6/-2=4/-2=-2
        
x2= -b-√36/2.a
    x2=-2-6/-2=-8/-2=+4
                  -
       s=(-2,4)