Question

qual a equação de (×+6) (3-×)=20​

Answer 1

$(x+6).(3-x)=20\\\\x~.~3~-x~.~x~+~6~.~3~-~x~.~6=20\\\\3x-x^2+18-6x=20\\\\-x^2-3x-2=0\\\\\boxed{x^2+3x+2=0}\\\\\\Bhaskara\\\\\Delta=3^2-4.1.2~=~9-8~=~\boxed{1}\\\\x=\frac{-3 \pm \sqrt{1}}{2~.~1}\\\\\\x'=\frac{-3+1}{2}=\frac{-2}{2}=\boxed{-1}\\\\x''=\frac{-3-1}{2}=\frac{-4}{2}=\boxed{-2}$

Resposta: As raizes da equação são x = -1 e x = -2