Answer:
is this weird but in all my years of school I've never learn something like this
I just ask this question on the SnapCalc app the answer is in the image
Answer:
Radius of sphere is 3 units.
Step-by-step explanation:
Volume of sphere is given by 
surface area of sphere is given by 
where r is the radius of the sphere.
Given that
The number of cubic units in the volume of a sphere is equal to the number of square units in the surface area of the sphere.
we equate formula of Volume of sphere and surface area of sphere
assuming r as the radius.
thus,

Thus, radius of sphere is 3 units.
Simple. Just add/subtract each term. 4n-2n=2n. 8m+7m=15m.
This is very basic stuff.