\(\text{If} \begin{vmatrix} 1 & x & x^2 \\ x & x^2 & 1 \\ x^2 & 1 & x \end{vmatrix} = 7\ \text{and}\ \triangle = \begin{vmatrix} x^3 - 1 & 0 & x - x^4 \\ 0 & x - x^3 & x^3 - 1 \\ x - x^4 & x^3 - 1 & 0 \end{vmatrix}, \text{then}\)