The product is equal zero if one of the factors is equal zero.Therefore:
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 .
X^2 + 9 + 7 = 20
X^2 +16 = 20
X^2 = 20-16
X^2 = 4
Root 4 = 2
X=2
We know a or b != 0
but a-b==0 so both are the same unknown number
b/a must = 1
so
a/b is equivalent to b/a as a/b=1 as well.
So the last answer choice.
Area of Shaded triangle as a whole: 136cm^2
Area of Rectangle 1 : 20cm^2
Area of Rectangle 2 : 6cm ^ 2
Area of the shaded region :
136 - (20+6)
136 - (26)
110 cm^2