Question

me ajudeeeeeemmmm ;))

Answer 1

$\triangle=(-4)^2-4.1.(-5)=16+20=36$

$x_1=\frac{4+\sqrt{36} }{2.1}=\frac{4+6}{2}=\frac{10}{2}=5$

$x_2=\frac{4-\sqrt{36} }{2.1}=\frac{4-6}{2}=\frac{-2}{2}=-1$

$S=\{-1,5\}$