Question 1056073
This and your other two exercises are based purely on the definition of a parabola.  See these two lessons:


<a href="https://www.youtube.com/watch?v=M8LGsQMwwj4">equation of parabola using distance formula, given directrix and focus</a>


<a href="https://www.youtube.com/watch?v=Wworlx39KfQ">Same idea, but vertex not at origin, and different orientation</a>