8. Perform the indicated operation.
\[
\left[\begin{array}{cc}
6 & -6 \\
3 & -8
\end{array}\right]-\left[\begin{array}{cc}
-4 & -3 \\
-7 & 4
\end{array}\right]
\]

Step 1 ：We are given two matrices and asked to subtract them. The matrices are: \n\[\left[\begin{array}{cc} 6 & -6 \\ 3 & -8 \end{array}\right] \text{ and } \left[\begin{array}{cc} -4 & -3 \\ -7 & 4 \end{array}\right]\n\]

Step 2 ：To subtract two matrices, they must have the same dimensions. In this case, both matrices are 2x2, so we can subtract them.

Step 3 ：We subtract corresponding elements in the matrices to get the result. The result is: \n\[\left[\begin{array}{cc} 10 & -3 \\ 10 & -12 \end{array}\right]\n\]

Step 4 ：Final Answer: The result of the subtraction of the two matrices is \n\[\boxed{ \left[\begin{array}{cc} 10 & -3 \\ 10 & -12 \end{array}\right] }\n\]