I need your help please, how to find the radius of sphere

Question

The formula for the surface area of sphere is SA=4π². if the sphere is 4πx²-8πx+4π, what is the measure of the radius?

Answer 1

SA = 4pix^2 + 8pix + 4pi^2

= 4pi(x^2 + 2x + 1)

= 4pi(x+1)^2 =4pir^2

divide both sides by 4pi

(x+1)^2 = r^2

r^2 = (x+1)^2

take the square root of both sides

r = + or - (x+1)

r = x+1 units

if x>-1

or r= -x-1

if x<-1 = the sphere's radius

Answer 2