Given x^2 - 6x + 11 = (x + a)^2 + b, where x is real.
(a) Find the values of a and b.
Hence write down the least values of x^2 - 6x + 11
(b) Using (a), or otherwise,
write down the range of possible values of 1/(x^2 - 6x + 11)
(a) a = -3 b = 2 the least value = 2