Let $Q \in \mathbb{R}^{n\times n}$ be symmetric, $a \in \mathbb{R}^n$ and $c \in \mathbb{R}$.
And we have the following function:
$f(x) = x^tQx - ax + c \quad$ for $ x \in \mathbb{R}^n$
Question: Is there a way to immediately tell the roots of this function, similar to the pq-formula or such? Since $Ax - b = 0$ leads to the easy solution $x = A^{-1}b$ I was wondering if one could do the same on the quadratic version.