does anyone have the mark scheme for this

[gusty garden]

realise that a bunch of squares added together >= 0
expand brackets to get (a^2 + b^2 + g^2) >= n by roots of polynomials
(a+b+g)^2 - 2(ab + ag + bg) >=n
(a+b+g)^2 >= 3n
m^2 >= 3n

where a,b,g are alpha, beta, gamma respectively