Solve for `x:|{:(x,x),(8,x):}| = |{:(7,-2,1),(0,3,-1),(5,-4,2):}|`.

Explanation

To solve the equation \( | \begin{pmatrix} x & x \\ 8 & x \end{pmatrix} | = | \begin{pmatrix} 7 & -2 & 1 \\ 0 & 3 & -1 \\ 5 & -4 & 2 \end{pmatrix} | \), we will follow these steps:

### Step 1: Calculate the determinant of the 2x2 matrix
The determinant of a 2x2 matrix \( \begin{pmatrix} A & B \\ C & D \end{pmatrix} \) is given by the formula:
\[ | \begin{pmatrix} A & B \\ C & D \end{pmatrix} | = AD - BC \]
For our matrix \( \begin{pmatrix} x & x \\ 8 & x \end{pmatrix} \), we have:
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