Answer:
Vertex: (3,5)
Focus: (3,8)
Directrix: y = 2
Explanation:
Get y by itself by adding 5 over to the other side. The equation is now y = 1/12(x-3)^2 + 5.
The value inside of the parentheses is -3. Since it's within the parentheses, switch the signs for the x value of the vertex. The "+ 5" represents the y value. Therefore the vertex is (3,5).
The value "a" on the parabola is 1/12. To find the distance from the vertex to the focus/directrix, use the equation a = 1/4p. 1/12 = 1/4p. p = 3. This parabola opens up, so "p" must be added onto the y value of the vertex for the focus. The focus is therefore (3,8).
For the directrix, subtract "p" from the y value of the vertex. The directrix is a horizontal line at y = 2.