Question

Dentre os numeros -2,0,1,4 quais deles sao raizes da equaçao x²-2x-8=0

Answer 1

$x^{2} -2x-8=0= \Delta= b^{2} -4.a.c= -2^{2} -4.1.(-8)= \Delta=4+32=36 x^{1} =-+(-2) \sqrt{36} /2=2-6/2=-4/2=-2 x^{2} =-+(-2) \sqrt{36} /2=2+6/2=8/2=4$



S{-2,4}

Answer 2

Vamos aplicar .

$x^2-2x-8=0\\\Delta=(-2)^2-4.1(-8)\\\Delta=4+32\\\Delta=36$

$x= \frac{-b\pm \sqrt{\Delta} }{2a}$

$x= \frac{2\pm6}{2}$

$x_1= \frac{2+6}{2}$

$\boxed{x_1=4}$

$x_2= \frac{2-6}{2}$

$\boxed{x_2=-2}$

$\boxed{\boxed{S=\{4,-2\}}}$