What are the values of x that satisfy the equation $$\left| {\matrix{ x & 0 & 2 \cr {2x} & 2 & 1 \cr 1 & 1 & 1 \cr } } \right| + \left| {\matrix{ {3x} & 0 & 2 \cr {{x^2}} & 2 & 1 \cr 0 & 1 & 1 \cr } } \right| = 0$$ ?

What is the value of the determinant $$\left| {\matrix{ {1!} & {2!} & {3!} \cr {2!} & {3!} & {4!} \cr {3!} & {4!} & {5!} \cr } } \right|$$ ?

What is the value of the determinant of the inverse of the matrix $\begin{bmatrix} -4 & -5 \\ 2 & 2 \end{bmatrix} ?$

The system of equations 15y - 10x + 50 = 0, 2x - 3y - 5 = 0