ANSWER
![(y + 7)^2= - 52(x-3)](https://img.qammunity.org/2020/formulas/mathematics/high-school/ot4qtnplntswvgoeh7kbbts6jshm58b36s.png)
It was given that the parabola has its focus at:
(-10,-7)
and directrix at:
x=16.
We need to determine the vertex of this parabola which is midway between the focus and the directrix.
Therefore the vertex will be at,
![( (16 + - 10)/(2) , - 7)](https://img.qammunity.org/2020/formulas/mathematics/high-school/izphxocqi5u9hpene1lib6or7h0t920bgq.png)
![(3, - 7)](https://img.qammunity.org/2020/formulas/mathematics/high-school/je3wyubgiur01m8yz1xr0ksvj0584cwz43.png)
The equation of this parabola is of the form:
![(y-k)^2=4p(x-h)](https://img.qammunity.org/2020/formulas/mathematics/high-school/encmg5wbyr4mzv2o5pjj7xbc99nque88j1.png)
where p is the distance from the vertex to the focus.
![|p| = 16 - 3 = 13](https://img.qammunity.org/2020/formulas/mathematics/high-school/8sfvu339d23reeoa7wmntmfqwwl877zxdm.png)
Since the parabola opens towards the negative direction of the x-axis,
![p = - 13](https://img.qammunity.org/2020/formulas/mathematics/high-school/isimu9o7a4ibrsyj4tldsc1pu32zksbocj.png)
We substitute the vertex and the value for p to get;
![(y - - 7)^2=4( - 13)(x-3)](https://img.qammunity.org/2020/formulas/mathematics/high-school/13mlv6rmu6vx57u76mwp1ipa00oe4x2ok8.png)
![(y + 7)^2= - 52(x-3)](https://img.qammunity.org/2020/formulas/mathematics/high-school/ot4qtnplntswvgoeh7kbbts6jshm58b36s.png)