Question

8. Determine as raízes da equação x2 - X
- 12 = 0.
a) S={-3,4)
b) S={3,4)
c) S=(-4,-3)
d) S={-4,3}​

Answer 1

$x^2-x-12=0$

$\triangle=(-1)^2-4.1.(-12)=1+48=49$

$x_1=\frac{1+\sqrt{49} }{2.1}=\frac{1+7}{2}=\frac{8}{2}=4$

$x_2=\frac{1-\sqrt{49} }{2.1}=\frac{1-7}{2}=\frac{-6}{2}=-3$

$S=\{-3,4\}$