1. What number must be added to both sides of the equation $x^2 - 16x = 5$ to complete the square?
2. When solving the equation $x^2 + 8x - 3 = 0$ by completing the square, the equation can be written as $(x+4)^2 = k$. The value of $k$ is ___.
3. After completing the square, the equation $x^2 - 2x - 10 = 0$ is transformed into which of the following?
4. The solutions to the equation $x^2 - 4x - 8 = 0$ are of the form $x = 2 \pm \sqrt{k}$. What is the value of $k$? ___
5. To solve $3x^2 - 18x = 12$ by completing the square, the first step is to divide by 3. This gives $x^2 - 6x = 4$. After completing the square, the equation becomes $(x-3)^2 = \text{\_\_\_}$.
6. Solve $3(8x - 7)^2 = 24$ by extracting roots. Give the exact values.