Directrix

To find the Directrix of an equation, follow the following steps:
1. Write the equation of your parabola. For example, the equation might be (x- 12)^2 = 8 (y - 5)
2. Divide the coefficient in front of the parenthesis on the right side of the equation by 4. In this example, the result is 8/4 = 2
3. Subtract the number obtained from the coefficient in the parenthesis on the right side of the equation. In this example, 5 - 2 = 3
4. the number obtained is the Directrix!

-Josh