Answer:
C
Step-by-step explanation:
For any point (x, y) on the parabola the focus and directrix are equidistant
Using the distance formula
[tex]\sqrt{x^2+(y-5)^2}[/tex] = | y + 5 | ← square both sides
x² + (y - 5)² = (y + 5)² ← expand parenthesis on both sides
x² + y² - 10y + 25 = y² + 10y + 25 ( subtract y² - 10y + 25 from both sides )
x² = 20y
