Answer:
Step-by-step explanation:
When the quadratic is written in vertex form:
x = a(y -k)^2 +h
the vertex is (x, y) = (h, k), and the length of the latus rectum is 1/a.
For your given equation, ...
x = (1/2)(y -5)^2 +7
you have a=1/2, k = 5, h = 7, so ...
the vertex is (7, 5)
the length of the latus rectum is 1/(1/2) = 2