complete the square
since a=1 for ax²+bx²+c=0
we can do
take 1/2 of the linear coefient and square it
-6/2=-3, (-3)²=9
add that to both sides
x²-3x+9-25=9
factor perfect square trinomial
(x-3)²-25=9
add 25 to both sides
(x-3)²=34
sqrt both sides, rmember to take positive and negative roots
x-3=+/-√34
add 3
x=3+/-√34
x=3+√34 or 3-√34