What is 9 +10?
It is 21
\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\begin{pmatrix} 1\\ 2 \end{pmatrix}\sum_{}^{}\begin{bmatrix} 1 && 2 \\ 3 && 4 \end{bmatrix}=21\)
It's 19...
PS. I got the joke