Question

como resolvo essa equacao do 2 grau : 2x²-4x-8=0

Answer 1

$2x^2-4x-8=0 \ \div2\\\\ x^2-2x-4-0\\\\ x^2-2x-4+1-1=0\\\\ x^2-2x+1-5=0\\\\ (x-1)^2=5\\\\ (x-1)=\pm\sqrt{5} \\\\ x-1= \sqrt{5} \\ x= \sqrt{5}+1\\\\ x-1= -\sqrt{5} \\ x= -\sqrt{5}+1$