Question

-5X2+20=0
equacão do segundo grau incompleta

Answer 1

$-5x^2+20=0\\ \\ -5x^2=-20\\ \\ x^2=\frac{-20}{-5}\\ \\ x^2=4\\ \\ x=\pm\sqrt4\\ \\ x=\pm2\\ \\ S=\{\pm2\}$