Разложить на множители:
х²+4х+1=

D = 4^2 - 4*1*1 = 16-4 = 12x1 = (-4+sqrt(12))/2 = (-4+2sqrt(3))/2 = -2 + sqrt(3)x2 = (-4-sqrt(12))/2 = (-4-2sqrt(3))/2 = -2 - sqrt(3)x^2+4x + 1 = (x - (-2+sqrt3))*(x-(-2-sqrt3)) = (x + 2 - sqrt3)*(x + 2+sqrt3)