Answer:
x = 9±sqrt(7)
Step-by-step explanation:
3(x-9)^2 =21
Divide each side by 3
3/3(x-9)^2 =21/3
(x-9)^2 =7
Take the square root of each side
sqrt((x-9)^2) =±sqrt(7)
x-9 =±sqrt(7)
Add 9 to each side
