Question

me ajudem, por favor.
x² - 6x -7=0​

Answer 1

Resposta:

S={-1,7}

Explicação passo-a-passo:

vamos calcular as raizes pelo método tradicional

a=1

b=-6

c=-7

$\delta=b^{2}-4.a.c\\\delta=(-6)^{2}-4.1.-7\\\delta=36+28\\\delta=64\\\\x_{1}=\frac{-b+\sqrt{\delta}}{2.a}\\x_{1}=\frac{-(-6)+\sqrt{64}}{2.1}\\x_{1}=\frac{6+8}{2}\\x_{1}=\frac{14}{2}\\x_{1}=7\\\\x_{2}=\frac{-b-\sqrt{\delta}}{2.a}\\x_{2}=\frac{-(-6)-\sqrt{64}}{2.1}\\x_{2}=\frac{6-8}{2}\\x_{2}=\frac{-2}{2}\\x_{2}=-1$

logo a solução é:

S{-1,7}