What is x (x-5)^2-72=0

(x-5)^2-72=0      add 72 to both sides

(x-5)^2  = 72      take the square root of both sides

x - 5  = ±√72

x - 5  = ±√(36 * 2) =

x - 5  = ±6√( 2)    add 5 to both sides

x = 5 ± 6√( 2)