Ok, I am stuck on this hyperboloid equation.

Find the equation of the hyperboloid of one sheet passing through the points https://webwork.math.lsu.edu/webwork...6d7e3ae161.png and https://webwork.math.lsu.edu/webwork...935f219a21.png.

I know the general equation for the single sheet hyperboloid which is :

I have found (a) and (b) in the above equation, but how do I find (c)?

Thanks!!(Hi)