Answer:
x=[tex]\frac{1}{20}[/tex][tex](y-5)^{2}[/tex]-1
Step-by-step explanation:
since directrix is parallel to y-axis, it is a horizontal parabola,
x=a(y-k)^2-h
the difference between directrix and focus is 10, so p=5
p=1/4a=5
solve for a, a=1/20
horizontal focus (p,0): (5,0) --> (4,5) meaning shift 1 left, 5 up (h=1, k=5)
