`ax^3+bx^2+cx+d=0`,	`Галактика®`
k=0,	a=1, b=0, c=-3, d=-2
p=c/a-3(b/3a)^2, q=-cb/3a^2+2(b/3a)^3+d/a
D=(p/3)^3+(q/2)^2
U=-q/2+√D, V=-q/2-√D
y_k=0
y_k=u_k-p/3u_k, u_k=e^((ln|U|+i(arg(U)+2πk))/3),	U≠0, k∈ℤ,	`Viete®u`
y_k=v_k-p/3v_k, v_k=e^((ln|V|+i(arg(V)+2πk))/3),	V≠0, k∈ℤ,	`Viete®v`
u=∛U, v=∛V
y0=u+v,	D>=0,	`Fontata®`
y1=-(u+v)/2+√(-3)((u-v)/2),	D>=0,	`Fontata®`
y2=-(u+v)/2-√(-3)((u-v)/2),	D>=0,	`Fontata®`
y_k=2√(-p/3)cos((1/3)arccos(((3q)/(2p))√(-3/p))-(2πk)/3),	D<0, k∈ℤ,	`Viete®D`
x=x_k, x_k=y_k-b/3a