SOLUTION: How do I find the latus rectum of (x-1)^2=-8(y+1) Thank You

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Question 929975: How do I find the latus rectum of (x-1)^2=-8(y+1)
Thank You
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
the vertex form of a Parabola opening up(a>0) or down(a<0),
y=a%28x-h%29%5E2+%2Bk
where(h,k) is the vertex and x = h is the Line of Symmetry ,
the focus is (h,k + p), With Directrix y = (k - p), a = 1/(4p)
.........
(x-1)^2 =-8(y+1)
y = (-1/8)(x-1)^2 -1
1/(4p) = -1/8, p = -2
latus rectum 8units in length (horizontal blue LINE segment thru the focus)