Question

Which is the equation of a circle with center (-5, 2) and radius sqrt 7}?

Answer 1

Circle equation: `(x-x_c)^2+(y-y_c)^2=r^2`
where `(x_c,y_c)` is the center and `r` is the radius

Explanation:

In your case:
The center is `(-5,2)` and the radius is `r=sqrt(7)` `=>`
`(x-(-5))^2+(y-2)^2=(sqrt(7))^2`
`(x+5)^2+(y-2)^2=7`

The circle equation can be written in many forms, some examples are here.