The formula of the line is
y=mx + b
The likes goes through the point (0,0)
that means that y-int = 0, b=0
y=mx
So we need to find only slope.

Given :
Center of sphere , C( 1 , -1 , 6 ) .
To Find :
Find equations of the spheres with center (1, −1, 6) that touch the following planes.a) xy-plane b) yz-plane c) xz-plane .
Solution :
a)
Distance of the point from xy-plane is :
d = 6 units .
So , equation of circle with center C and radius 6 units is :

b)
Distance of point from yz-plane is :
d = 1 unit .
So , equation of circle with center C and radius 1 units is :

c)
Distance of point from xz-plane is :
d = 1 unit .
So , equation of circle with center C and radius 1 units is :

Hence , this is the required solution .
2x^2-4=124 is the correct answer.