To factor the expression \( p^2 - 6 - q(p^2 - 6)^2 \), let's start by introducing a substitution to simplify our calculations. Let:
\[ x = p^2 - 6. \]
Now, we can rewrite the expression as:
\[ x - qx^2. \]
Next, we can factor this expression:
\[ x(1 - qx). \]
Now, substituting back \( x = p^2 - 6 \), we have:
\[ (p^2 - 6)(1 - q(p^2 - 6)). \]
Thus, the factored form of the original expression \( p^2 - 6 - q(p^2 - 6)^2 \) is:
\[ (p^2 - 6)(1 - q(p^2 - 6)). \]