If $a, b$ and $c$ are real numbers such that $a^2+b^2+c^2-a b-b c-a c \leq 0$, then $$…
If $a, b$ and $c$ are real numbers such that $a^2+b^2+c^2-a b-b c-a c \leq 0$, then
$$
\left|\begin{array}{ccc}
(a-b+1)^5 & b^7-c^7 & c^9-a^9 \\
a^{11}-b^{11} & (b-c+2)^3 & c^{13}-a^{13} \\
a^{15}-b^{15} & b^{17}-c^{17} & (c-a+3)^1
\end{array}\right|=
$$