(x+1)(x+9)
x2-6x+9 = (x-3)(x-3) when factorised.
(x-9)(x+9)
x2 + 13x + 36 = (x + 9)(x + 4)
x2 + 9 + 20 = x2 + 29, and can not be factored.I assume though that you mis-wrote your question, and what you in fact want to ask is how to factor x2 + 9x + 20.In that case, the answer is (x + 4)(x + 5).
(x + 4)(x + 9)
(x + 3)(x + 3)
x - 3
x2 - 14x + 45 = (x - 5)(x - 9).
(x+3)(x+3)
3(x2 - 2x + 3)
(x - 3)(x - 3)