So this question was asked in an online quiz. The definiteness of the quadratic form
Q(x) = 8$x_1^2$ + 7$x_2^2$ + 3$x_3^2$ - 12$x_1x_2$ - 8$x_2x_3$ + 4$x_3x_2$
I made the following matrix: \begin{bmatrix}8&-6&0\\-6&7&-4\\0&-4&3\end{bmatrix} Any help would be appreciated.
P.S.: I don't need the explanation on how to solve these type of questions, that is already in my notes. Just the solution please.