Answer:
x = 11
x = 7
Step-by-step explanation:
divide each side by 3 to get:
(x-4)² = 9
(x-4)² is the difference of two squares and has these factors:
(x+2)(x-2) = 9
x + 2 = 9; x = 7
x - 2 = 9; x = 11
