Question

Решите уравнение x^2-4x-3=0

Answer 1

$x^2-4x-3=0\\ D=b^2-4ac=(-4)^2-4*(-3)=16+12=28=4*7\\ x_{1,2}=frac{-bpmsqrt{D}}{2a}=frac{-(-4)pmsqrt{4*7}}{2*1}=frac{4pm2sqrt{2}}{2}=frac{2*(2pmsqrt{2})}{2}=2pmsqrt{2}$