LOG2(x - 3) - 2·LOG2(x) + 2 = LOG2(1/(x - 6))
LOG2(x - 3) - LOG2(x^2) + LOG2(4) = LOG2(1/(x - 6))
LOG2(4·(x - 3)/x^2) = LOG2(1/(x - 6))
4·(x - 3)/x^2 = 1/(x - 6)
4·(x - 3)·(x - 6) = x^2
4·(x^2 - 9·x + 18) = x^2
4·x^2 - 36·x + 72 = x^2
3·x^2 - 36·x + 72 = 0
x^2 - 12·x + 24 = 0
x = 6 ± 2·√3