Solve the polynomial equation using special products (x-3)^2=36.

We notice that if we'll subtract both sides 36, we'll get
a difference of two squares:

(x-3)^2 - 36 =
0

We know that the difference of two squares returns the
product:

a^2 - b^2 =
(a-b)(a+b)

Let a = x - 3 and b =
6

(x-3)^2 - 36 = (x - 3 - 6)(x - 3 +
6)

We'll cancel each
factor:

(x - 3 - 6) = 0

x - 9
= 0

x = 9

(x - 3 + 6) =
0

x + 3 = 0

x =
-3

The solutions of the polynomial equation
are {-3 ; 9}.