Question

resolva -x² -2x + 15 = 0

Answer 1

Olá, bom dia ☺

Resolução;

-x² -2x + 15 = 0

Coeficientes:

a=-1,b=-2,c=15

Valor do discriminante:

$\Delta=b^2-4.a.c \\ \Delta=(-2)^2-4.(-1).15 \\ \Delta=4+60 \\ \Delta=64$


Valores de x:

$x= \dfrac{-b\pm \sqrt{\Delta} }{2.a} \\ \\ x= \dfrac{-(-2)\pm \sqrt{64} }{2.(-1)} \\ \\ x= \dfrac{2\pm8}{-2} \\ \\ x'= \dfrac{2+8}{-2}= \dfrac{10}{-2} =-5 \\ \\ x''= \dfrac{2-8}{-2} = \dfrac{-6}{-2}= 3$

S={-5,3}

Bons estudos :)