Need asap!
the equation of a parabola is
(y - 1)^2 = 16 (x + 3)
what is the equation of the directrix of the parabola

We see it is the y terms squared so it opens left or right

in form
(y-k)^2=4(p)(x-h)
vertex is (h,k)
and p is distance from focus to vertex, also distance from vertex to directix
if p>0, then it opens to the right and dirextix is to the left of vertex
if p<0, then it opens to the left and directix is tothe right of vertex

so
(y-1)^2=4(4)(x-(-3))
vertex is (-3,1)
4>0 so dirextix is to left of vertex
left is in x direction
-3-4=-7
directix is x=-7

270 books in each shelves

The answer is 49/16 or 3 1/16