Question

Решите уравнение x^2-4x-3=0

Answer 1

$x^2-4x-3=0\\\\ D=b^2-4ac=(-4)^2-4*(-3)=16+12=28=4*7\\\\ x_{1,2}=\frac{-b\pm\sqrt{D}}{2a}=\frac{-(-4)\pm\sqrt{4*7}}{2*1}=\frac{4\pm2\sqrt{2}}{2}=\frac{2*(2\pm\sqrt{2})}{2}=2\pm\sqrt{2}$