how to solve

m^2 + 8m + 3 =0
m^2 + 8m = -3

m^2 + 8m + 16 = -3 + 16
(m + 4)^2 + 16 = -3+16
(m + 4)^2 = -3+16
(m + 4)^2 = 13

(m + 4) = ±sqrt(13)
m = ±sqrt(13) - 4

m ₁ = -sqrt(13) - 4
m ₂ = sqrt(13) - 4

[input]x^2 + 8x + 3 =0[/input]