Question

What are the solutions to 3(x−9)2=−180

Answer 1

(I am going to need some clarifications from you later.)

We expand the bracket :
3(x-9)2 = 6(x-9) = 6x - 54.

Add each side by 180 :

6x - 54 + 180 = 0
-> 6x + 126 = 0.
-> x = (0-126)/6 = -21.