Answer:
x = 3±sqrt(20)
Step-by-step explanation:
(x-3)^2-20=0
Add 20 to each side
(x-3)^2-20+20=0+20
(x-3)^2=20
Take the square root of each side
sqrt((x-3)^2) = ±sqrt(20)
(x-3) = ±sqrt(20)
Add 3 to each side
x-3+3 = 3±sqrt(20)
